Index: /trunk/src/VBox/Frontends/VirtualBox/src/widgets/UIMiniToolBar.cpp
===================================================================
--- /trunk/src/VBox/Frontends/VirtualBox/src/widgets/UIMiniToolBar.cpp	(revision 61883)
+++ /trunk/src/VBox/Frontends/VirtualBox/src/widgets/UIMiniToolBar.cpp	(revision 61884)
@@ -380,9 +380,26 @@
 }
 
+/* static */
+Qt::WindowFlags UIMiniToolBar::defaultWindowFlags()
+{
+#ifdef VBOX_WS_X11
+    /* Depending on current WM: */
+    switch (vboxGlobal().typeOfWindowManager())
+    {
+        /* Frameless top-level window for Unity, issues with tool window there.. */
+        case X11WMType_Compiz: return Qt::Window | Qt::FramelessWindowHint;
+        default: break;
+    }
+#endif /* VBOX_WS_X11 */
+
+    /* Frameless tool window by default: */
+    return Qt::Tool | Qt::FramelessWindowHint;
+}
+
 UIMiniToolBar::UIMiniToolBar(QWidget *pParent,
                              GeometryType geometryType,
                              Qt::Alignment alignment,
                              bool fAutoHide /* = true */)
-    : QWidget(pParent, Qt::Tool | Qt::FramelessWindowHint)
+    : QWidget(pParent, defaultWindowFlags())
     /* Variables: General stuff: */
     , m_geometryType(geometryType)
Index: /trunk/src/VBox/Frontends/VirtualBox/src/widgets/UIMiniToolBar.h
===================================================================
--- /trunk/src/VBox/Frontends/VirtualBox/src/widgets/UIMiniToolBar.h	(revision 61883)
+++ /trunk/src/VBox/Frontends/VirtualBox/src/widgets/UIMiniToolBar.h	(revision 61884)
@@ -65,4 +65,7 @@
 
 public:
+
+    /** Proposes default set of window flags for particular platform. */
+    static Qt::WindowFlags defaultWindowFlags();
 
     /** Constructor, passes @a pParent to the QWidget constructor.