funny behavior in splitter window

Hello, I put together a small gui using wxpython, I attached my sample code. There is funny behavior when you pull the sash down. I only get this to occur with the grid and treectrl in place – that is, if I replace the tree and grid control with two textctrl’s I don’t get the same funny drawing to occur. Any ideas of what might be happening? Thanks.

Jeff

App1.py (440 Bytes)

Frame1.py (3.67 KB)