Activate the driver when getting a show event, and clear the GUI Editor display widget when there's no GUI loaded.

code/studio/src/plugins/gui_editor/nel3d_widget.cpp

@@ -102,6 +102,13 @@ namespace GUIEditor
 		driver->swapBuffers();
 	}
 
+	void Nel3DWidget::showEvent( QShowEvent *evnt )
+	{
+		QWidget::showEvent( evnt );
+
+		if( driver != NULL )
+			driver->activate();
+	}
 
 #if defined ( NL_OS_WINDOWS )
 

code/studio/src/plugins/gui_editor/nel3d_widget.h

@@ -55,6 +55,8 @@ namespace GUIEditor
 
 	protected:
 
+		void showEvent( QShowEvent *evnt );
+
 #if defined(NL_OS_WINDOWS)
 	virtual bool winEvent( MSG *message, long *result );
 #elif defined(NL_OS_MAC)

code/studio/src/plugins/gui_editor/nelgui_ctrl.cpp

@@ -153,6 +153,10 @@ namespace GUIEditor
 				w->getDriver()->EventServer.pump();
 				draw();
 			}
+			else
+			{
+				w->clear();
+			}
 		}
 	}