Index: /trunk/src/VBox/Frontends/VirtualBox/src/extensions/QIMainWindow.cpp
===================================================================
--- /trunk/src/VBox/Frontends/VirtualBox/src/extensions/QIMainWindow.cpp	(revision 81255)
+++ /trunk/src/VBox/Frontends/VirtualBox/src/extensions/QIMainWindow.cpp	(revision 81256)
@@ -27,4 +27,9 @@
 # include "UICommon.h"
 # include "UIDesktopWidgetWatchdog.h"
+#endif
+
+/* Other VBox includes: */
+#ifdef VBOX_WS_MAC
+# include "iprt/cpp/utils.h"
 #endif
 
@@ -103,5 +108,5 @@
 {
 #ifdef VBOX_WS_MAC
-    return ::darwinIsWindowMaximized(this);
+    return ::darwinIsWindowMaximized(unconst(this));
 #else
     return isMaximized();