Isn't this the default behavior? for as long as I rememeber if a panel in the SplitterWindow gets to small (i.e. if the sash is dragged to one of the ends) the SplitterWindow unsplits. I've allways got around it by setting the minimum size of pane to something like 1 px. 
路路路
On Tue, 20 Jul 2004 15:37:33 -0700, Robin Dunn <robin@alldunn.com> wrote:
Jean-Michel Fauth wrote:
2) I have to face one another issue. When resizing a main frame containing a
SplitterWindow, making it as small a possible and enlarging it again, I can not catch
the sash again. It has desappeared. This happens in the demo too.
It seems there is a real bug here.Enter a bug report about this one.
--
Peter Damoc
Hacker Wannabe
http://www.sigmacore.net/