Index: dll/win32/uxtheme/nonclient.c
===================================================================
--- dll/win32/uxtheme/nonclient.c	(revision 71259)
+++ dll/win32/uxtheme/nonclient.c	(working copy)
@@ -814,6 +814,9 @@
 
     SetCapture(hWnd);
 
+    /* Set a default value for ht */
+    ht = 0;
+
     for (;;)
     {
         if (GetMessageW(&Msg, 0, WM_MOUSEFIRST, WM_MOUSELAST) <= 0)
@@ -837,7 +840,8 @@
         }
     }
 
-    ThemeDrawCaptionButtons(&context, ht, 0);
+    /* Default to wParam if we break without setting ht */
+    ThemeDrawCaptionButtons(&context, ht ? ht : wParam, 0);
     ThemeCleanupDrawContext(&context);
 
     ReleaseCapture();