Index: /trunk/src/VBox/Frontends/VirtualBox/src/UIMediumTypeChangeDialog.cpp
===================================================================
--- /trunk/src/VBox/Frontends/VirtualBox/src/UIMediumTypeChangeDialog.cpp	(revision 37884)
+++ /trunk/src/VBox/Frontends/VirtualBox/src/UIMediumTypeChangeDialog.cpp	(revision 37885)
@@ -33,13 +33,17 @@
 /* Constructor: */
 UIMediumTypeChangeDialog::UIMediumTypeChangeDialog(QWidget *pParent, const QString &strMediumId)
-    : QIWithRetranslateUI<QDialog>(pParent)
+    : QIWithRetranslateUI<QIDialog>(pParent)
 {
+#ifdef Q_WS_MAC
+    setWindowFlags(Qt::Sheet);
+#else /* Q_WS_MAC */
+    /* Enable size-grip: */
+    setSizeGripEnabled(true);
+#endif /* Q_WS_MAC */
+
     /* Search for corresponding medium: */
     m_medium = vboxGlobal().findMedium(strMediumId).medium();
     m_oldMediumType = m_medium.GetType();
     m_newMediumType = m_oldMediumType;
-
-    /* Enable size-grip: */
-    setSizeGripEnabled(true);
 
     /* Create main layout: */
@@ -91,5 +95,5 @@
     }
     /* Accept dialog with parent class method: */
-    QIWithRetranslateUI<QDialog>::accept();
+    QIWithRetranslateUI<QIDialog>::accept();
 }
 
@@ -98,5 +102,5 @@
 {
     /* Reject dialog with parent class method: */
-    QIWithRetranslateUI<QDialog>::reject();
+    QIWithRetranslateUI<QIDialog>::reject();
 }
 
Index: /trunk/src/VBox/Frontends/VirtualBox/src/UIMediumTypeChangeDialog.h
===================================================================
--- /trunk/src/VBox/Frontends/VirtualBox/src/UIMediumTypeChangeDialog.h	(revision 37884)
+++ /trunk/src/VBox/Frontends/VirtualBox/src/UIMediumTypeChangeDialog.h	(revision 37885)
@@ -20,8 +20,6 @@
 #define __UIMediumTypeChangeDialog_h__
 
-/* Global includes: */
-#include <QDialog>
-
 /* Local includes: */
+#include "QIDialog.h"
 #include "QIWithRetranslateUI.h"
 #include "COMDefs.h"
@@ -35,5 +33,5 @@
 
 /* Dialog providing user with possibility to change medium type: */
-class UIMediumTypeChangeDialog : public QIWithRetranslateUI<QDialog>
+class UIMediumTypeChangeDialog : public QIWithRetranslateUI<QIDialog>
 {
     Q_OBJECT;