Strange freezing after updating from another thread

[Chris Seaton <chris chrisseaton com>]

I have a GUI thread and a worker thread. I use gdk_thread_enter/leave to 
 restrict GUI calls to a single thread.
The GUI thread starts the worker thread and then shows a modal dialog 
with a progress bar that blocks the GUI thread (although continues to 
process messages, like any modal dialog).
When the worker thread is done is closes the modal dialog, allowing the 
GUI thread to continue and the user to continue working with the main 
window.
Everything is cool, except when the dialog closes all the widgets in the 
main window stop resizing! They all still work, redraw and everything, 
they just won't resize.
What could be causing this?

Thanks.

Chris Seaton