diff --git a/static/boot.js b/static/boot.js
index e967f292..af545ef1 100644
--- a/static/boot.js
+++ b/static/boot.js
@@ -201,11 +201,8 @@ function syncWorkspacePanelUI(){
   const clearBtn=$('btnClearPreview');
   if(clearBtn){
     clearBtn.disabled=!isOpen;
-    _setButtonTooltip(clearBtn, hasPreview?'Close preview':'Hide workspace panel');
-    // On desktop, only show the X button when a file preview is open.
-    // In browse mode the chevron (btnCollapseWorkspacePanel) already serves
-    // as the close control, so showing both produces a duplicate X.
-    if(!isCompact) clearBtn.style.display=hasPreview?'':'none';
+    _setButtonTooltip(clearBtn, hasPreview?'Close preview':'Close');
+    if(!isCompact) clearBtn.style.display='';
   }
 }
 
diff --git a/static/index.html b/static/index.html
index c32974ce..592e6243 100644
--- a/static/index.html
+++ b/static/index.html
@@ -1181,17 +1181,15 @@
   <aside class="rightpanel">
     <div class="resize-handle" id="rightpanelResize"></div>
     <div class="panel-header">
-      <span id="workspacePanelHeading" class="workspace-panel-heading" title="Workspace">Workspace</span><span id="workspaceHiddenIndicator" class="workspace-hidden-indicator" data-i18n-title="workspace_hidden_files_visible_title" title="Hidden files are visible — click for options" hidden onclick="toggleWorkspacePrefsMenu(event)"><svg width="11" height="11" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2.4" stroke-linecap="round" stroke-linejoin="round" aria-hidden="true"><path d="M1 12s4-8 11-8 11 8 11 8-4 8-11 8-11-8-11-8z"/><circle cx="12" cy="12" r="3"/></svg><span data-i18n="workspace_hidden_files_visible">hidden visible</span></span>
+      <div class="workspace-panel-title-group"><span id="workspacePanelHeading" class="workspace-panel-heading" title="Workspace">Workspace</span><span id="workspaceHiddenIndicator" class="workspace-hidden-indicator" data-i18n-title="workspace_hidden_files_visible_title" title="Hidden files are visible — click for options" hidden onclick="toggleWorkspacePrefsMenu(event)"><svg width="11" height="11" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2.4" stroke-linecap="round" stroke-linejoin="round" aria-hidden="true"><path d="M1 12s4-8 11-8 11 8 11 8-4 8-11 8-11-8-11-8z"/><circle cx="12" cy="12" r="3"/></svg><span data-i18n="workspace_hidden_files_visible">hidden visible</span></span></div>
       <span class="git-badge" id="gitBadge" style="display:none"></span>
       <div class="panel-actions">
-        <button class="panel-icon-btn has-tooltip has-tooltip--bottom" id="btnCollapseWorkspacePanel" data-tooltip="Hide workspace panel" onclick="toggleWorkspacePanel(false)"><svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" aria-hidden="true"><polyline points="15 18 9 12 15 6"/></svg></button>
         <button class="panel-icon-btn has-tooltip has-tooltip--bottom" id="btnUpDir" data-tooltip="Parent directory" onclick="navigateUp()" style="display:none"><svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" aria-hidden="true"><line x1="12" y1="19" x2="12" y2="5"/><polyline points="5 12 12 5 19 12"/></svg></button>
         <button class="panel-icon-btn has-tooltip has-tooltip--bottom" id="btnNewFile" data-tooltip="New file" onclick="promptNewFile()"><svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" aria-hidden="true"><line x1="12" y1="5" x2="12" y2="19"/><line x1="5" y1="12" x2="19" y2="12"/></svg></button>
         <button class="panel-icon-btn has-tooltip has-tooltip--bottom" id="btnNewFolder" data-tooltip="New folder" onclick="promptNewFolder()"><svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" aria-hidden="true"><path d="M22 19a2 2 0 0 1-2 2H4a2 2 0 0 1-2-2V5a2 2 0 0 1 2-2h5l2 3h9a2 2 0 0 1 2 2z"/></svg></button>
         <button class="panel-icon-btn has-tooltip has-tooltip--bottom" id="btnRefreshPanel" data-tooltip="Refresh" onclick="if(S.session)loadDir(S.currentDir)"><svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" aria-hidden="true"><polyline points="23 4 23 10 17 10"/><polyline points="1 20 1 14 7 14"/><path d="M3.51 9a9 9 0 0 1 14.85-3.36L23 10M1 14l4.64 4.36A9 9 0 0 0 20.49 15"/></svg></button>
         <button class="panel-icon-btn has-tooltip has-tooltip--bottom" id="btnWorkspacePrefs" data-tooltip="Workspace options" data-i18n-title="workspace_options" aria-haspopup="true" aria-expanded="false" onclick="toggleWorkspacePrefsMenu(event)"><svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" aria-hidden="true"><circle cx="12" cy="5" r="1.5"/><circle cx="12" cy="12" r="1.5"/><circle cx="12" cy="19" r="1.5"/></svg><span class="workspace-prefs-dot" id="workspacePrefsDot" hidden></span></button>
         <button class="panel-icon-btn close-preview has-tooltip has-tooltip--bottom" id="btnClearPreview" data-tooltip="Close preview"><svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" aria-hidden="true"><line x1="18" y1="6" x2="6" y2="18"/><line x1="6" y1="6" x2="18" y2="18"/></svg></button>
-        <button class="panel-icon-btn mobile-close-btn" onclick="handleWorkspaceClose()" title="Close" aria-label="Close workspace panel">×</button>
       </div>
     </div>
     <div class="breadcrumb-bar" id="breadcrumbBar" style="display:none"></div>
diff --git a/static/style.css b/static/style.css
index ea551f96..f21f68aa 100644
--- a/static/style.css
+++ b/static/style.css
@@ -1279,19 +1279,17 @@
      panel's width so the header can collapse less-essential elements as the
      user resizes the panel narrower. */
   .rightpanel{width:300px;background:var(--sidebar);border-left:1px solid var(--border);display:flex;flex-direction:column;overflow:hidden;flex-shrink:0;min-width:0;opacity:1;transform:translateX(0);transform-origin:right center;transition:width .24s cubic-bezier(.22,1,.36,1),opacity .18s ease,transform .24s cubic-bezier(.22,1,.36,1),border-color .24s ease;container-type:inline-size;container-name:rightpanel;}
-  /* Collapse priority as the panel narrows: git-badge first, then "Workspace"
-     label, never the icon buttons. flex-shrink ratios give graceful ellipsis;
-     @container queries below cut to display:none at hard breakpoints. */
-  .panel-header{padding:12px 16px;border-bottom:1px solid var(--border);font-size:11px;font-weight:600;color:var(--muted);text-transform:uppercase;letter-spacing:.1em;display:flex;align-items:center;gap:6px;overflow:visible;}
-  .panel-header > span:first-child{white-space:nowrap;overflow:hidden;text-overflow:ellipsis;min-width:0;flex-shrink:2;}
+  .panel-header{padding:12px 16px;border-bottom:1px solid var(--border);font-size:11px;font-weight:600;color:var(--muted);text-transform:uppercase;letter-spacing:.1em;display:grid;grid-template-columns:minmax(0,1fr) auto;align-items:center;gap:6px;overflow:visible;}
+  .workspace-panel-title-group{grid-column:1;grid-row:1;display:flex;align-items:center;min-width:0;}
+  .workspace-panel-title-group > span:first-child{white-space:nowrap;overflow:hidden;text-overflow:ellipsis;min-width:0;}
   .workspace-panel-heading{cursor:default;border-radius:6px;padding:2px 4px;margin:-2px -4px;}
   .workspace-panel-heading.workspace-panel-heading--enabled{cursor:pointer;}
   .workspace-panel-heading.workspace-panel-heading--enabled:hover,
   .workspace-panel-heading.workspace-panel-heading--enabled:focus-visible{color:var(--text);background:var(--hover-bg);outline:none;}
-  .git-badge{font-size:9px;font-weight:600;color:var(--muted);background:var(--hover-bg);padding:2px 7px;border-radius:4px;letter-spacing:.02em;white-space:nowrap;font-family:'SF Mono',ui-monospace,monospace;flex-shrink:3;overflow:hidden;min-width:0;}
+  .git-badge{grid-column:1 / -1;grid-row:2;justify-self:start;font-size:9px;font-weight:600;color:var(--muted);background:var(--hover-bg);padding:2px 7px;border-radius:4px;letter-spacing:.02em;white-space:nowrap;font-family:'SF Mono',ui-monospace,monospace;overflow:hidden;min-width:0;max-width:100%;}
   .topbar-source-badge{display:inline-flex;align-items:center;margin-left:6px;padding:2px 7px;border-radius:999px;background:var(--accent-bg);color:var(--accent-text);font-size:10px;font-weight:700;letter-spacing:.02em;vertical-align:middle;}
   .git-badge.dirty{color:var(--accent-text);background:var(--accent-bg);}
-  .panel-actions{display:flex;gap:4px;flex-shrink:0;margin-left:auto;}
+  .panel-actions{grid-column:2;grid-row:1;display:flex;gap:4px;flex-shrink:0;margin-left:auto;}
 
   /* Crisp display:none at narrow widths so the header doesn't show a sliver
      of an ellipsised label or git badge — icons survive longest. */
@@ -1299,9 +1297,8 @@
     .git-badge{display:none !important;}
   }
   @container rightpanel (max-width: 160px){
-    .panel-header > span:first-child{display:none;}
+    .workspace-panel-title-group{display:none;}
   }
-  .mobile-close-btn{display:none;}
   .panel-icon-btn{width:24px;height:24px;background:none;border:none;color:var(--muted);cursor:pointer;border-radius:5px;font-size:13px;display:flex;align-items:center;justify-content:center;transition:all .15s;}
   .panel-icon-btn:hover{background:var(--hover-bg);color:var(--text);}
   .panel-icon-btn:disabled{opacity:.35;cursor:not-allowed;}
@@ -1310,7 +1307,6 @@
   /* file-item-actions removed: delete button is now a flex child */
   .file-action-btn{width:20px;height:20px;background:rgba(0,0,0,.4);border:none;border-radius:4px;color:var(--muted);cursor:pointer;font-size:11px;display:flex;align-items:center;justify-content:center;}
   .file-action-btn:hover{color:var(--accent);}
-  .close-preview{cursor:pointer;opacity:.6;}.close-preview:hover{opacity:1;}
   /* Breadcrumb navigation */
   .breadcrumb-bar{display:flex;align-items:center;gap:2px;padding:6px 12px;font-size:12px;border-bottom:1px solid var(--border);flex-shrink:0;overflow:hidden;white-space:nowrap;}
   /* ── Workspace prefs kebab menu (#1793) ─────────────────────────── */
@@ -1437,9 +1433,6 @@
   @media(max-width:900px){
     .rightpanel{display:none}
     .workspace-toggle-btn,.mobile-files-btn{display:inline-flex!important;}
-    .mobile-close-btn{display:flex;}
-    .close-preview{display:none;}
-    #btnCollapseWorkspacePanel{display:none;}
   }
 
   @container composer-footer (max-width: 700px){
@@ -1539,11 +1532,8 @@
       box-shadow:none!important;}
     .rightpanel.mobile-open{right:0!important;box-shadow:-4px 0 24px rgba(0,0,0,.4)!important;}
     .rightpanel .resize-handle{display:none;}
-    .rightpanel .panel-header{display:grid;grid-template-columns:minmax(0,1fr) auto;row-gap:8px;}
-    .rightpanel .panel-header > span:first-child{grid-column:1;min-width:0;}
-    .rightpanel .git-badge{grid-column:2;justify-self:end;}
-    .rightpanel .panel-actions{grid-column:1 / -1;width:100%;align-items:center;gap:8px;justify-content:flex-start;margin-left:0;}
-    .rightpanel .mobile-close-btn{margin-left:auto;min-width:36px;min-height:36px;}
+    .rightpanel .panel-header{row-gap:8px;}
+    .rightpanel .panel-actions{align-items:center;gap:8px;}
     /* Topbar adjustments */
     .topbar{padding:8px 12px;gap:8px;}
     .topbar-title{font-size:14px;}
diff --git a/tests/test_issue781.py b/tests/test_issue781.py
index ea5f7106..93cf9cfd 100644
--- a/tests/test_issue781.py
+++ b/tests/test_issue781.py
@@ -1,12 +1,12 @@
 """
-Tests for issue #781 — duplicate X close button in workspace preview header
-on window resize below 900px breakpoint.
+Tests for issue #781 — duplicate X close button in workspace preview header.
+
+The fix: a single btnClearPreview (.close-preview) is the only close button,
+visible on all devices. The mobile-close-btn element was removed entirely.
 
 Verifies that:
-  - .close-preview is hidden (display:none) inside the @media (max-width:900px) block
-  - .mobile-close-btn is shown (display:flex) inside the same @media block
-Both rules must appear inside the same @media(max-width:900px) block so that
-at mobile widths only the mobile-close-btn is visible.
+  - .close-preview is NOT hidden by any media query (visible everywhere)
+  - .mobile-close-btn has no CSS rules remaining (element removed from HTML)
 """
 
 import re
@@ -44,88 +44,33 @@ def _extract_media_block(css, media_query_pattern):
     raise AssertionError("Unmatched brace in CSS after @media block")
 
 
-def _strip_media_blocks(css):
-    """Remove all @media {...} blocks from CSS, returning base rules only."""
-    result = []
-    i = 0
-    while i < len(css):
-        # Look for @media keyword
-        m = re.search(r"@media\b", css[i:])
-        if not m:
-            result.append(css[i:])
-            break
-        # Append everything before this @media
-        result.append(css[i : i + m.start()])
-        # Find the opening brace of this @media block
-        brace_start = css.index("{", i + m.start())
-        depth = 0
-        j = brace_start
-        while j < len(css):
-            if css[j] == "{":
-                depth += 1
-            elif css[j] == "}":
-                depth -= 1
-                if depth == 0:
-                    i = j + 1
-                    break
-            j += 1
-        else:
-            break
-    return "".join(result)
-
-
 _MEDIA_900_PATTERN = r"@media\s*\(\s*max-width\s*:\s*900px\s*\)"
 
 
-def test_mobile_close_btn_displayed_in_900px_block():
-    """mobile-close-btn must be display:flex inside the 900px media query."""
+def test_close_preview_not_hidden_in_900px_block():
+    """The single close button (.close-preview) must NOT be hidden in any media query."""
     css = _load_css()
     block = _extract_media_block(css, _MEDIA_900_PATTERN)
-    assert ".mobile-close-btn" in block, (
-        ".mobile-close-btn rule is missing from @media(max-width:900px) block"
-    )
-    rule_match = re.search(r"\.mobile-close-btn\s*\{([^}]*)\}", block)
-    assert rule_match, ".mobile-close-btn rule body not found in 900px block"
-    assert "display:flex" in rule_match.group(1).replace(" ", ""), (
-        ".mobile-close-btn should have display:flex in the 900px media query"
+    assert ".close-preview" not in block, (
+        ".close-preview must not appear in @media(max-width:900px) block — "
+        "the single X button should be visible on all devices"
     )
 
 
-def test_close_preview_hidden_in_900px_block():
-    """.close-preview must be display:none inside the 900px media query (fix for #781)."""
+def test_mobile_close_btn_not_in_css():
+    """mobile-close-btn CSS rules should have been removed entirely."""
     css = _load_css()
-    block = _extract_media_block(css, _MEDIA_900_PATTERN)
-    assert ".close-preview" in block, (
-        ".close-preview rule is missing from @media(max-width:900px) block — "
-        "the duplicate-button fix (#781) may have been reverted"
-    )
-    rule_match = re.search(r"\.close-preview\s*\{([^}]*)\}", block)
-    assert rule_match, ".close-preview rule body not found in 900px block"
-    assert "display:none" in rule_match.group(1).replace(" ", ""), (
-        ".close-preview should have display:none in the 900px media query to hide "
-        "the duplicate desktop X button at mobile widths"
+    assert ".mobile-close-btn" not in css, (
+        ".mobile-close-btn CSS rule still present — the element was removed "
+        "from HTML so its styles should be cleaned up too"
     )
 
 
-def test_both_rules_in_same_media_block():
-    """Both .close-preview and .mobile-close-btn must appear in the same 900px block."""
+def test_close_preview_visible_in_base_css():
+    """Outside media queries, .close-preview must NOT be display:none."""
     css = _load_css()
-    block = _extract_media_block(css, _MEDIA_900_PATTERN)
-    assert ".mobile-close-btn" in block, (
-        ".mobile-close-btn missing from @media(max-width:900px) block"
-    )
-    assert ".close-preview" in block, (
-        ".close-preview missing from @media(max-width:900px) block"
-    )
-
-
-def test_close_preview_visible_outside_media_query():
-    """Outside the media query, .close-preview must NOT be display:none
-    (it should remain visible on desktop)."""
-    css = _load_css()
-    base_css = _strip_media_blocks(css)
-    close_rules = re.findall(r"\.close-preview\s*\{([^}]*)\}", base_css)
-    for rule_body in close_rules:
-        assert "display:none" not in rule_body.replace(" ", ""), (
-            ".close-preview must not be hidden in base (desktop) CSS"
+    # Simple check: find all .close-preview rules and ensure none set display:none
+    for m in re.finditer(r"\.close-preview\s*\{([^}]*)\}", css):
+        assert "display:none" not in m.group(1).replace(" ", ""), (
+            ".close-preview must not be hidden by any CSS rule"
         )
diff --git a/tests/test_mobile_layout.py b/tests/test_mobile_layout.py
index b4e02e7d..46ac1972 100644
--- a/tests/test_mobile_layout.py
+++ b/tests/test_mobile_layout.py
@@ -205,16 +205,8 @@ def test_rightpanel_mobile_slide_over_css():
     assert re.search(r'\.rightpanel\.mobile-open\{[^}]*box-shadow:\s*-4px 0 24px rgba\(0,\s*0,\s*0,\s*\.?4\)',
                      rightpanel_block, re.DOTALL), \
         "open mobile rightpanel should keep the edge shadow"
-    assert re.search(r'\.rightpanel\s+\.panel-header\{[^}]*display:\s*grid[^}]*grid-template-columns:\s*minmax\(0,1fr\)\s+auto', rightpanel_block), \
-        "mobile workspace header should use a compact two-row grid"
-    assert re.search(r'\.rightpanel\s+\.panel-header\s*>\s*span:first-child\{[^}]*grid-column:\s*1', rightpanel_block), \
-        "mobile workspace heading should stay on the first row"
-    assert re.search(r'\.rightpanel\s+\.git-badge\{[^}]*grid-column:\s*2[^}]*justify-self:\s*end', rightpanel_block), \
-        "mobile git badge should share the first row with the heading"
-    assert re.search(r'\.rightpanel\s+\.panel-actions\{[^}]*grid-column:\s*1 / -1[^}]*width:\s*100%', rightpanel_block), \
-        "mobile workspace actions should span the full second row"
-    assert re.search(r'\.rightpanel\s+\.mobile-close-btn\{[^}]*margin-left:\s*auto', rightpanel_block), \
-        "mobile workspace close button should align to the far right"
+    assert re.search(r'\.rightpanel\s+\.panel-header\{[^}]*row-gap:\s*8px', rightpanel_block), \
+        "mobile workspace header should keep comfortable row spacing"
 
 
 def test_workspace_panel_inline_width_is_desktop_only():
diff --git a/tests/test_sprint41.py b/tests/test_sprint41.py
index f2d72ec1..eee0898c 100644
--- a/tests/test_sprint41.py
+++ b/tests/test_sprint41.py
@@ -1,15 +1,11 @@
 """
-Sprint 41 Tests: Title auto-generation fix + mobile close button CSS (PR #333).
+Sprint 41 Tests: Title auto-generation fix (PR #333).
 
 Covers:
 - streaming.py: sessions titled 'New Chat' trigger auto-title generation
 - streaming.py: sessions with empty/falsy title trigger auto-title generation
 - streaming.py: sessions titled 'Untitled' (original guard) still trigger
 - streaming.py: sessions with a user-set title do NOT trigger auto-title
-- style.css: .mobile-close-btn is hidden by default (desktop rule present)
-- style.css: .mobile-close-btn shown in <=900px media query
-- style.css: #btnCollapseWorkspacePanel hidden in <=900px media query
-- index.html: both .mobile-close-btn and #btnCollapseWorkspacePanel buttons exist
 """
 import pathlib
 import re
@@ -59,71 +55,6 @@ class TestTitleAutoGenerationCondition(unittest.TestCase):
             "Expected at least 3 OR-joined sub-conditions (Untitled, New Chat, not s.title)")
 
 
-# ── style.css: mobile close button visibility ─────────────────────────────
-
-class TestMobileCloseButtonCSS(unittest.TestCase):
-    """Verify CSS rules that control the duplicate close button on mobile."""
-
-    def test_mobile_close_btn_hidden_by_default(self):
-        """Desktop default: .mobile-close-btn must be display:none outside any media query."""
-        # Find the rule before the first @media block that contains mobile-close-btn
-        # We look for the pattern in the desktop (non-media-query) section
-        self.assertIn(
-            ".mobile-close-btn{display:none;}",
-            CSS.replace(" ", ""),
-            ".mobile-close-btn should be hidden by default (desktop) — rule missing or wrong"
-        )
-
-    def test_mobile_close_btn_shown_in_900px_query(self):
-        """Inside max-width:900px media query, .mobile-close-btn must be display:flex."""
-        # Extract the 900px media block
-        m = re.search(r'@media\s*\(max-width\s*:\s*900px\)\s*\{([^{}]*(?:\{[^{}]*\}[^{}]*)*)\}',
-                      CSS)
-        self.assertIsNotNone(m, "@media(max-width:900px) block not found in style.css")
-        block = m.group(1).replace(" ", "")
-        self.assertIn(".mobile-close-btn{display:flex;}",
-                      block,
-                      ".mobile-close-btn must be display:flex inside the 900px media query")
-
-    def test_desktop_collapse_btn_hidden_in_900px_query(self):
-        """Inside max-width:900px media query, #btnCollapseWorkspacePanel must be display:none."""
-        m = re.search(r'@media\s*\(max-width\s*:\s*900px\)\s*\{([^{}]*(?:\{[^{}]*\}[^{}]*)*)\}',
-                      CSS)
-        self.assertIsNotNone(m, "@media(max-width:900px) block not found in style.css")
-        block = m.group(1).replace(" ", "")
-        self.assertIn("#btnCollapseWorkspacePanel{display:none;}",
-                      block,
-                      "#btnCollapseWorkspacePanel must be display:none in 900px media query")
-
-    def test_900px_query_retains_existing_rules(self):
-        """Ensure the PR didn't accidentally drop existing rules from the 900px block."""
-        m = re.search(r'@media\s*\(max-width\s*:\s*900px\)\s*\{([^{}]*(?:\{[^{}]*\}[^{}]*)*)\}',
-                      CSS)
-        self.assertIsNotNone(m)
-        block = m.group(1)
-        self.assertIn("rightpanel", block, ".rightpanel rule missing from 900px block")
-        self.assertIn("mobile-files-btn", block, ".mobile-files-btn rule missing from 900px block")
-
-
-# ── index.html: button presence ───────────────────────────────────────────
-
-class TestWorkspacePanelButtons(unittest.TestCase):
-    """Verify both panel buttons are present in the HTML so CSS rules have targets."""
-
-    def test_desktop_collapse_button_exists(self):
-        self.assertIn("btnCollapseWorkspacePanel", HTML,
-                      "#btnCollapseWorkspacePanel button must exist in index.html")
-
-    def test_mobile_close_button_exists(self):
-        self.assertIn("mobile-close-btn", HTML,
-                      ".mobile-close-btn button must exist in index.html")
-
-    def test_mobile_close_button_has_aria_label(self):
-        """Accessibility: mobile close button must have an aria-label."""
-        m = re.search(r'class="[^"]*mobile-close-btn[^"]*"[^>]*>', HTML)
-        self.assertIsNotNone(m, "Could not find mobile-close-btn element")
-        self.assertIn("aria-label", m.group(0),
-                      "mobile-close-btn must have aria-label for accessibility")
 
 
 class TestIssue495TitleStreaming(unittest.TestCase):
diff --git a/tests/test_sprint44.py b/tests/test_sprint44.py
index 9dcb09fe..91001096 100644
--- a/tests/test_sprint44.py
+++ b/tests/test_sprint44.py
@@ -1,15 +1,13 @@
 """
-Sprint 44 Tests: Workspace panel close button fixes (PR #413).
+Sprint 44 Tests: Workspace panel close button (PR #413).
 
 Covers:
-- index.html: mobile-close-btn now calls handleWorkspaceClose() instead of
-  closeWorkspacePanel(), so hitting X while a file is open returns you to the
-  file browser rather than collapsing the whole panel.
-- boot.js: syncWorkspacePanelUI() hides #btnClearPreview (the X icon) on
-  desktop when no file preview is open, eliminating the duplicate X that
-  appeared alongside the chevron collapse button.
-- boot.js: handleWorkspaceClose() logic — clears preview when one is visible,
-  closes panel otherwise (existing function, confirmed wired to both buttons).
+- btnClearPreview is the single close button for all devices. Clicking it calls
+  handleWorkspaceClose(), which clears a file preview if open, or closes the
+  entire workspace panel otherwise.
+- The mobile-close-btn element was removed — only one X button remains.
+- Tooltip text updated to "Close" (when no preview) and "Close preview"
+  (when a file is being viewed).
 """
 import pathlib
 import re
@@ -20,113 +18,79 @@ HTML = (REPO / "static" / "index.html").read_text(encoding="utf-8")
 BOOT_JS = (REPO / "static" / "boot.js").read_text(encoding="utf-8")
 
 
-class TestMobileCloseButtonBehavior(unittest.TestCase):
-    """mobile-close-btn must call handleWorkspaceClose(), not closeWorkspacePanel()."""
+class TestSingleCloseButton(unittest.TestCase):
+    """btnClearPreview is the only close button, visible on all devices."""
 
-    def test_mobile_close_btn_calls_handle_workspace_close(self):
-        """mobile-close-btn onclick must be handleWorkspaceClose(), not closeWorkspacePanel()."""
-        m = re.search(r'class="[^"]*mobile-close-btn[^"]*"[^>]*>', HTML)
-        self.assertIsNotNone(m, "mobile-close-btn element not found in index.html")
-        btn_html = m.group(0)
-        self.assertIn(
-            'onclick="handleWorkspaceClose()"',
-            btn_html,
-            "mobile-close-btn must call handleWorkspaceClose() so that hitting X "
-            "while a file is open closes the file first, not the whole panel",
-        )
-
-    def test_mobile_close_btn_does_not_call_close_workspace_panel_directly(self):
-        """mobile-close-btn must NOT call closeWorkspacePanel() directly."""
-        m = re.search(r'class="[^"]*mobile-close-btn[^"]*"[^>]*>', HTML)
-        self.assertIsNotNone(m, "mobile-close-btn element not found in index.html")
-        btn_html = m.group(0)
-        self.assertNotIn(
-            'onclick="closeWorkspacePanel()"',
-            btn_html,
-            "mobile-close-btn must not call closeWorkspacePanel() directly — "
-            "it would bypass the two-step close logic and collapse the panel even "
-            "when a file is being viewed",
-        )
-
-    def test_handle_workspace_close_defined_in_boot_js(self):
-        """handleWorkspaceClose() must be defined in boot.js."""
-        self.assertIn(
-            "function handleWorkspaceClose()",
-            BOOT_JS,
-            "handleWorkspaceClose() is missing from boot.js",
-        )
-
-    def test_handle_workspace_close_clears_preview_first(self):
-        """handleWorkspaceClose() must call clearPreview() when a preview is visible."""
-        # The function must check for visible preview and call clearPreview
-        self.assertIn(
-            "clearPreview()",
-            BOOT_JS,
-            "handleWorkspaceClose() must call clearPreview() when preview is visible",
-        )
-    def test_handle_workspace_close_falls_back_to_close_panel(self):
-        """handleWorkspaceClose() must call closeWorkspacePanel() as fallback."""
-        # Find the function start and extract until the closing brace by scanning
-        start = BOOT_JS.find("function handleWorkspaceClose()")
-        self.assertNotEqual(start, -1, "handleWorkspaceClose() not found in boot.js")
-        # Extract a generous window after the function start
-        fn_window = BOOT_JS[start : start + 400]
-        self.assertIn(
-            "closeWorkspacePanel()",
-            fn_window,
-            "handleWorkspaceClose() must call closeWorkspacePanel() as its fallback path",
-        )
-
-
-class TestDesktopNoDuplicateXButton(unittest.TestCase):
-    """On desktop, only one X/close control should appear at a time."""
-
-    def test_sync_workspace_panel_ui_hides_clear_preview_on_desktop(self):
-        """syncWorkspacePanelUI() must set display:none on btnClearPreview when no preview and desktop."""
-        self.assertIn(
-            "clearBtn.style.display",
-            BOOT_JS,
-            "syncWorkspacePanelUI() must control clearBtn.style.display to hide it "
-            "on desktop when no file preview is open",
-        )
-
-    def test_clear_preview_hidden_when_no_preview(self):
-        """The display toggle for btnClearPreview must key off hasPreview."""
-        # Expect something like: clearBtn.style.display=hasPreview?'':'none'
-        # or clearBtn.style.display = hasPreview ? '' : 'none'
-        pattern = r"clearBtn\.style\.display\s*=\s*hasPreview"
-        self.assertRegex(
-            BOOT_JS,
-            pattern,
-            "btnClearPreview display must be conditioned on hasPreview in "
-            "syncWorkspacePanelUI() to avoid a duplicate X on desktop",
-        )
-
-    def test_clear_preview_toggle_only_applied_on_desktop(self):
-        """The display toggle must be guarded by !isCompact so mobile is unaffected."""
-        # Expect: if(!isCompact) clearBtn.style.display=...
-        pattern = r"isCompact.*clearBtn\.style\.display|clearBtn\.style\.display.*isCompact"
-        self.assertRegex(
-            BOOT_JS,
-            pattern,
-            "btnClearPreview display toggle must be guarded by isCompact so the "
-            "mobile X button visibility is not accidentally affected",
-        )
-
-    def test_btnclearpreview_exists_in_html(self):
-        """#btnClearPreview must still exist in the HTML (not removed)."""
+    def test_btn_clear_preview_exists_in_html(self):
+        """#btnClearPreview must exist in index.html."""
         self.assertIn(
             'id="btnClearPreview"',
             HTML,
-            "#btnClearPreview must remain in index.html",
+            "#btnClearPreview must be present in index.html",
         )
 
-    def test_btncollapseWorkspacepanel_exists_in_html(self):
-        """#btnCollapseWorkspacePanel (chevron) must still exist in the HTML."""
-        self.assertIn(
-            'id="btnCollapseWorkspacePanel"',
+    def test_mobile_close_btn_removed_from_html(self):
+        """mobile-close-btn element should no longer exist in index.html."""
+        self.assertNotIn(
+            "mobile-close-btn",
             HTML,
-            "#btnCollapseWorkspacePanel must remain in index.html",
+            "mobile-close-btn was removed — only btnClearPreview remains as close control",
+        )
+
+    def test_btn_clear_preview_wired_to_handle_workspace_close(self):
+        """btnClearPreview onclick must be handleWorkspaceClose."""
+        self.assertRegex(
+            BOOT_JS,
+            r"btnClearPreview.*onclick\s*=\s*handleWorkspaceClose",
+            "btnClearPreview must call handleWorkspaceClose so that clicking X "
+            "either clears a preview or closes the panel",
+        )
+
+
+class TestHandleWorkspaceCloseLogic(unittest.TestCase):
+    """handleWorkspaceClose() clears preview first, falls back to close panel."""
+
+    def test_function_defined(self):
+        self.assertIn(
+            "function handleWorkspaceClose()",
+            BOOT_JS,
+            "handleWorkspaceClose() must exist in boot.js",
+        )
+
+    def test_clears_preview_when_open(self):
+        idx = BOOT_JS.find("function handleWorkspaceClose()")
+        self.assertGreater(idx, 0, "handleWorkspaceClose() not found")
+        body = BOOT_JS[idx:idx + 500]
+        self.assertIn(
+            "clearPreview()",
+            body,
+            "handleWorkspaceClose() must call clearPreview() when a preview is open",
+        )
+
+    def test_falls_back_to_close_panel(self):
+        idx = BOOT_JS.find("function handleWorkspaceClose()")
+        self.assertGreater(idx, 0, "handleWorkspaceClose() not found")
+        body = BOOT_JS[idx:idx + 500]
+        self.assertIn(
+            "closeWorkspacePanel()",
+            body,
+            "handleWorkspaceClose() must call closeWorkspacePanel() as fallback",
+        )
+
+
+class TestTooltipText(unittest.TestCase):
+    """The X button tooltip says 'Close' when no preview, 'Close preview' otherwise."""
+
+    def test_tooltip_uses_close(self):
+        """syncWorkspacePanelUI() sets tooltip to 'Close' (not 'Hide workspace panel')."""
+        idx = BOOT_JS.find("function syncWorkspacePanelUI()")
+        self.assertGreater(idx, 0, "syncWorkspacePanelUI() not found")
+        body = BOOT_JS[idx:idx + 2000]
+        # The tooltip line should contain 'Close' and NOT 'Hide workspace panel'
+        self.assertIn(
+            "'Close'",
+            body,
+            "btnClearPreview tooltip must use 'Close' instead of 'Hide workspace panel'",
         )
 
 
diff --git a/tests/test_workspace_panel_session_list.py b/tests/test_workspace_panel_session_list.py
index 501fb53b..c5ddcac9 100644
--- a/tests/test_workspace_panel_session_list.py
+++ b/tests/test_workspace_panel_session_list.py
@@ -74,20 +74,20 @@ class TestWorkspacePanelCollapsePriority:
         # in #1775 so its tooltip pseudo-elements can escape the header bar
         # (otherwise the workspace-panel header tooltips like "New file" get
         # clipped). The title-text ellipsis is preserved by the inner span
-        # `.panel-header > span:first-child` which has its own
+        # `.workspace-panel-title-group > span:first-child` which has its own
         # overflow:hidden + text-overflow:ellipsis. So we check that EITHER
         # the parent uses overflow:hidden (legacy) or that the inner span
         # handles its own ellipsis (current).
         if "overflow:hidden" not in rule:
-            inner_span_idx = STYLE_CSS.find(".panel-header > span:first-child{")
+            inner_span_idx = STYLE_CSS.find(".workspace-panel-title-group > span:first-child{")
             assert inner_span_idx != -1, (
                 ".panel-header lost overflow:hidden but no inner span "
-                "rule (.panel-header > span:first-child) handles the "
+                "rule (.workspace-panel-title-group > span:first-child) handles the "
                 "title-text ellipsis as a fallback."
             )
             inner_rule = STYLE_CSS[inner_span_idx: STYLE_CSS.find("}", inner_span_idx) + 1]
             assert "overflow:hidden" in inner_rule and "text-overflow:ellipsis" in inner_rule, (
-                ".panel-header > span:first-child must own the ellipsis "
+                ".workspace-panel-title-group > span:first-child must own the ellipsis "
                 "behaviour now that the parent is overflow:visible."
             )
 
@@ -106,26 +106,21 @@ class TestWorkspacePanelCollapsePriority:
         )
 
     def test_workspace_label_shrinks_with_ellipsis(self):
-        """The "Workspace" label (`panel-header > span:first-child`) must
-        shrink with ellipsis truncation rather than overflow uncontrollably."""
+        """The "Workspace" label must shrink with ellipsis truncation."""
         # Find the rule
-        sel = ".panel-header > span:first-child"
+        sel = ".workspace-panel-title-group > span:first-child"
         idx = STYLE_CSS.find(sel)
         assert idx >= 0, f"Selector {sel!r} not found in style.css"
         rule = STYLE_CSS[idx: STYLE_CSS.find("}", idx)]
         assert "text-overflow:ellipsis" in rule
         assert "min-width:0" in rule
-        assert "flex-shrink:2" in rule  # shrinks before icons (icons are 0)
 
-    def test_git_badge_shrinks_first(self):
-        """`.git-badge` must shrink faster than the label so it disappears
-        first as the panel narrows."""
+    def test_git_badge_uses_second_row(self):
+        """`.git-badge` should sit beneath the title/action row."""
         idx = STYLE_CSS.find(".git-badge{")
         rule = STYLE_CSS[idx: STYLE_CSS.find("}", idx)]
-        assert "flex-shrink:3" in rule, (
-            ".git-badge must have flex-shrink:3 so it shrinks before the "
-            "label (flex-shrink:2) and the icons (flex-shrink:0)."
-        )
+        assert "grid-column:1 / -1" in rule
+        assert "grid-row:2" in rule
 
     def test_container_query_hides_git_badge_first(self):
         """At narrow widths the git badge gets `display:none` BEFORE the
@@ -145,7 +140,7 @@ class TestWorkspacePanelCollapsePriority:
         assert "@container rightpanel (max-width: 160px)" in STYLE_CSS
         idx = STYLE_CSS.find("@container rightpanel (max-width: 160px)")
         block = STYLE_CSS[idx: idx + 200]
-        assert ".panel-header > span:first-child{display:none" in block
+        assert ".workspace-panel-title-group{display:none" in block
 
     def test_breakpoints_in_correct_order(self):
         """Sanity: the git-badge breakpoint (220px) must be wider than the