Added AddGrab, RemoveGrab, IsGrabbed to wxTopLevelWindowGTK

and AddGrabIfNeeded to wxHtmlHelpController, to assist with
showing the help window from a modal dialog.


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@15880 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/html/helpfrm.cpp

@@ -1442,6 +1442,13 @@ void wxHtmlHelpFrame::OnCloseWindow(wxCloseEvent& evt)
     GetSize(&m_Cfg.w, &m_Cfg.h);
     GetPosition(&m_Cfg.x, &m_Cfg.y);
 
+#ifdef __WXGTK__
+    if (IsGrabbed())
+    {
+        RemoveGrab();
+    }
+#endif
+    
     if (m_Splitter && m_Cfg.navig_on) m_Cfg.sashpos = m_Splitter->GetSashPosition();
 
     if (m_Config)