error with revIDEHandleMouseUp ?

[Curt Ford]

A substack which has so far been behaving itself is acting strangely..  
when I open the substack from its mainstack (via a pulldown menu), the  
IDE seems to freeze; after a minute or so I get an error:

'The handler: revIDEHandleMouseUp has reached the recursion limit of:  
400000. Execution will be terminated to prevent hang.'

I can click 'OK' out of that, and if I click the pointer tool for edit  
mode immediately, I can work a little with the stack; as soon as I  
choose the browse tool to run it, it gets stuck again & shows the same  
error.

I can open the substack from the application browser but it freezes up  
immediately again when I choose the browse tool.

I didn't see anything about revIDEHandleMouseUp in the Quality Control  
Centre. Any suggestions how to start troubleshooting?

Running 3.5; upgraded to Mac OS X 10.5.7 just last night.. hmm..

thanks!

Curt
Sona Software LLC