diff --git a/src/qtgui/preview.ui b/src/qtgui/preview.ui
index 1cf53987..94f295dc 100644
--- a/src/qtgui/preview.ui
+++ b/src/qtgui/preview.ui
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <ui version="4.0">
  <class>Preview</class>
- <widget class="QWidget" name="Preview">
+ <widget class="QDialog" name="Preview">
   <property name="geometry">
    <rect>
     <x>0</x>
diff --git a/src/qtgui/preview_w.h b/src/qtgui/preview_w.h
index 31e20624..84dce328 100644
--- a/src/qtgui/preview_w.h
+++ b/src/qtgui/preview_w.h
@@ -108,7 +108,7 @@ private:
 };
 
 
-class Preview : public QWidget, public Ui::Preview {
+class Preview : public QDialog, public Ui::Preview {
     Q_OBJECT
 
 public: