1. added wxGTK::wxToolBar::SetToolShortHelp() and test for it in sample

2. fix a crash if SetSelection is called too early in wxTextCtrl
3. patch for mouse position in wxTreeCtrl events


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@8805 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/gtk/tbargtk.h

@@ -52,6 +52,8 @@ public:
 
     virtual wxToolBarToolBase *FindToolForPosition(wxCoord x, wxCoord y) const;
 
+    virtual void SetToolShortHelp(int id, const wxString& helpString);
+
     // implementation from now on
     // --------------------------