Applied #10917: wxGTK wxFileDialog::SetDirectory and ::SetFilename problems

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@62101 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

interface/wx/filedlg.h

@@ -197,6 +197,8 @@ public:
 
     /**
         Sets the default filename.
+        
+        In wxGTK this will have little effect unless a default directory has previously been set.
     */
     virtual void SetFilename(const wxString& setfilename);