Index: base/shell/explorer-new/traywnd.c
===================================================================
--- base/shell/explorer-new/traywnd.c	(revision 58352)
+++ base/shell/explorer-new/traywnd.c	(working copy)
@@ -1912,6 +1912,20 @@
     {
         This->Locked = bLock;
 
+        LONG_PTR lptrStyle = GetWindowLong(This->hWnd, GWL_STYLE);
+        if (This->Locked)
+        {
+            /* Resizing disabled, so, remove thick frame */
+            lptrStyle &= ~(WS_THICKFRAME);
+        }
+        else
+        {
+            lptrStyle |= (WS_THICKFRAME);
+        }
+
+        SetWindowLongPtr(This->hWnd, GWL_STYLE, lptrStyle);
+        SetWindowPos(This->hWnd, NULL, 0, 0, 0, 0, SWP_FRAMECHANGED | SWP_NOMOVE | SWP_NOSIZE | SWP_NOZORDER | SWP_NOOWNERZORDER);
+
         if (This->TrayBandSite != NULL)
         {
             if (!SUCCEEDED(ITrayBandSite_Lock(This->TrayBandSite,