Fixed showing of dock area when inserting a dock widget into a hidden dock area

fixed setting of DockAreaTabBar index to prevent showing of tab 0 when inserting a dock widget into an area with no current index tab

src/DockWidgetTab.cpp

@@ -570,7 +570,7 @@ void CDockWidgetTab::mouseDoubleClickEvent(QMouseEvent *event)
 void CDockWidgetTab::setVisible(bool visible)
 {
 	// Just here for debugging to insert debug output
-	Super::setVisible(visible);
+    Super::setVisible(visible);
 }