bug 981569. Don't ever remove our custom "is the window active" prope…

…rty. When switching from custom non-client margins to default non-client margins, send a `WM_NCACTIVATE` message so that `DefWindowProc` knows the correct active/inactive state of the window. r=blassey

widget/windows/nsWindow.cpp

@@ -2248,10 +2248,16 @@ nsWindow::SetNonClientMargins(nsIntMargin &margins)
       margins.right == -1 && margins.bottom == -1) {
     mCustomNonClient = false;
     mNonClientMargins = margins;
-    RemovePropW(mWnd, kManageWindowInfoProperty);
     // Force a reflow of content based on the new client
     // dimensions.
     ResetLayout();
+
+    int windowStatus =
+      reinterpret_cast<LONG_PTR>(GetPropW(mWnd, kManageWindowInfoProperty));
+    if (windowStatus) {
+      ::SendMessageW(mWnd, WM_NCACTIVATE, 1 != windowStatus, 0);
+    }
+
     return NS_OK;
   }
 
@@ -4671,6 +4677,7 @@ nsWindow::ProcessMessage(UINT msg, WPARAM& wParam, LPARAM& lParam,
        * WM_NCACTIVATE paints nc areas. Avoid this and re-route painting
        * through WM_NCPAINT via InvalidateNonClientRegion.
        */
+      UpdateGetWindowInfoCaptionStatus(FALSE != wParam);
 
       if (!mCustomNonClient)
         break;
@@ -4683,15 +4690,13 @@ nsWindow::ProcessMessage(UINT msg, WPARAM& wParam, LPARAM& lParam,
         // going active
         *aRetValue = FALSE; // ignored
         result = true;
-        UpdateGetWindowInfoCaptionStatus(true);
         // invalidate to trigger a paint
         InvalidateNonClientRegion();
         break;
       } else {
         // going inactive
         *aRetValue = TRUE; // go ahead and deactive
         result = true;
-        UpdateGetWindowInfoCaptionStatus(false);
         // invalidate to trigger a paint
         InvalidateNonClientRegion();
         break;
@@ -5205,7 +5210,6 @@ nsWindow::ProcessMessage(UINT msg, WPARAM& wParam, LPARAM& lParam,
     nsUXThemeData::CheckForCompositor(true);
 
     UpdateNonClientMargins();
-    RemovePropW(mWnd, kManageWindowInfoProperty);
     BroadcastMsg(mWnd, WM_DWMCOMPOSITIONCHANGED);
     NotifyThemeChanged();
     UpdateGlass();