Backed out changeset 9d9fe1cd50ec (bug 1930292) for causing Win11 visual regressions. CLOSED TREE

browser/base/content/browser-tabsintitlebar.js

@@ -69,9 +69,11 @@ var TabsInTitlebar = {
       !Object.keys(this._disallowed).length;
     if (allowed) {
       document.documentElement.setAttribute("tabsintitlebar", "true");
-      document.documentElement.setAttribute("chromemargin", "0,0,0,0");
       if (AppConstants.platform == "macosx") {
+        document.documentElement.setAttribute("chromemargin", "0,-1,-1,-1");
         document.documentElement.removeAttribute("drawtitle");
+      } else {
+        document.documentElement.setAttribute("chromemargin", "0,2,2,2");
       }
     } else {
       document.documentElement.removeAttribute("tabsintitlebar");

browser/base/content/browser.xhtml

@@ -17,7 +17,11 @@
 #endif
         data-l10n-args="{"content-title":"CONTENTTITLE"}"
         data-l10n-attrs="data-content-title-default, data-content-title-private, data-title-default, data-title-private"
-        chromemargin="0,0,0,0"
+#ifdef XP_WIN
+        chromemargin="0,2,2,2"
+#else
+        chromemargin="0,-1,-1,-1"
+#endif
         tabsintitlebar="true"
         windowtype="navigator:browser"
         macanimationtype="document"

mozglue/misc/PreXULSkeletonUI.cpp

@@ -1995,16 +1995,22 @@ static Result<Ok, PreXULSkeletonUIError> CreateAndStorePreXULSkeletonUIImpl(
   sCaptionHeight =
       sVerticalResizeMargin + sGetSystemMetricsForDpi(SM_CYCAPTION, sDpi);
 
-  // These match the offsets that we get with default prefs. We don't use the
+  // These match the margins set in browser-tabsintitlebar.js with default prefs
-  // skeleton ui if tabsInTitlebar is disabled, see bug 1673092.
+  // on Windows. We don't use the skeleton ui if tabsInTitlebar is disabled, see
+  // bug 1673092.
+  const Margin nonClientMargin{0, 2, 2, 2};
+
   if (sMaximized) {
     sNonClientOffset.top = sCaptionHeight - sVerticalResizeMargin;
   } else {
     // See nsWindow::NormalWindowNonClientOffset()
     sNonClientOffset.top = sCaptionHeight;
-    sNonClientOffset.bottom = sVerticalResizeMargin;
+    sNonClientOffset.bottom =
-    sNonClientOffset.left = sHorizontalResizeMargin;
+        std::min(sVerticalResizeMargin, nonClientMargin.bottom);
-    sNonClientOffset.right = sHorizontalResizeMargin;
+    sNonClientOffset.left =
+        std::min(sHorizontalResizeMargin, nonClientMargin.left);
+    sNonClientOffset.right =
+        std::min(sHorizontalResizeMargin, nonClientMargin.right);
   }
 
   if (sMaximized) {

toolkit/content/tests/browser/browser_findbar_marks.js

@@ -197,9 +197,8 @@ add_task(async function test_found_resize() {
   info(`values: ${JSON.stringify(values)}`);
   info(`resizedValues: ${JSON.stringify(resizedValues)}`);
   isfuzzy(resizedValues[0], values[0], 2, "first value");
-  const kSlop = 50;
+  Assert.greater(resizedValues[1] - 50, values[1], "second value");
-  Assert.greaterOrEqual(resizedValues[1] - kSlop, values[1], "second value");
+  Assert.greater(resizedValues[2] - 50, values[2], "third value");
-  Assert.greaterOrEqual(resizedValues[2] - kSlop, values[2], "third value");
 
   endFn();
 

toolkit/content/tests/chrome/window_maximized_persist_with_no_titlebar.xhtml

@@ -5,7 +5,7 @@
         height="300"
         width="300"
         sizemode="normal"
-        chromemargin="0,0,0,0"
+        chromemargin="0,2,2,2"
         id="window"
         persist="height width sizemode">
 <script type="application/javascript"><![CDATA[