fix drawing of the column move hint when the grid is scrolled to the right (#9776)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@55631 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/generic/grid.cpp

@@ -5580,6 +5580,7 @@ void wxGrid::ProcessColLabelMouseEvent( wxMouseEvent& event )
                     if ( markerX != m_dragLastPos )
                     {
                         wxClientDC dc( m_colLabelWin );
+                        DoPrepareDC(dc);
 
                         int cw, ch;
                         m_colLabelWin->GetClientSize( &cw, &ch );