refs #477, allow to detect an invisible dock widget parent by using CEnableForDockWidgetInfoArea for the view base

(by that I can tell if the parent dock widget is visible)

src/blackgui/components/enablefordockwidgetinfoarea.h

@@ -16,13 +16,13 @@
 #include "blackgui/dockwidgetinfoarea.h"
 #include "blackgui/infoarea.h"
 #include "blackgui/enableforframelesswindow.h"
+#include "blackmisc/qtconnectionlist.h"
 #include <QWidget>
 
 namespace BlackGui
 {
     namespace Components
     {
-
         //! Helper class: If a component is residing in an dockable widget.
         //! This class provides access to its info area and dockable widget.
         class BLACKGUI_EXPORT CEnableForDockWidgetInfoArea
@@ -34,6 +34,9 @@ namespace BlackGui
             //! Corresponding dockable widget in info area
             const BlackGui::CDockWidgetInfoArea *getDockWidgetInfoArea() const { return m_parentDockableInfoArea; }
 
+            //! Has dock area?
+            bool hasDockWidgetArea() const { return m_parentDockableInfoArea; }
+
             //! Corresponding dockable widget in info area
             //! \remarks Usually set from CDockWidgetInfoArea when it is fully initialized
             virtual bool setParentDockWidgetInfoArea(BlackGui::CDockWidgetInfoArea *parentDockableWidget);