Update column sizes after updating scrollbars, not before

As UpdateColumnSizes() uses client size, call it after the client size
is set correctly after adjusting scrollbars to the new virtual size.

src/generic/datavgen.cpp

@@ -3078,7 +3078,6 @@ void wxDataViewMainWindow::OnInternalIdle()
 
     if (m_dirty)
     {
-        UpdateColumnSizes();
         RecalculateDisplay();
         m_dirty = false;
     }
@@ -3098,6 +3097,7 @@ void wxDataViewMainWindow::RecalculateDisplay()
 
     SetVirtualSize( width, height );
     GetOwner()->SetScrollRate( 10, m_lineHeight );
+    UpdateColumnSizes();
 
     Refresh();
 }