I've checked the help

"The expression in SET FILTER TO has been re-entered while the filter is executing. This can happen with complex setups involving SET RELATION or SET FILTER, or during the use of Visual FoxPro functions or user-defined functions which reference other work areas, such as LOOKUP( ) or SEEK( )."

What this has anything to do with dock/undock? I don't know, but can be a bug if works well in VFP6.
Or can be the fact that VFP7 tries to save something related to windows position to resource file. Try with SET RESOURCE OFF.

Did you tried the updated version?



>Hi,
>I have try your, but still same error.
>
>'Expression has been re-entered while the filter is executing.' (1148) Occured In undock At Line 1!
>
>I have check my code to not call _screen.resize() in my frmmain.resize(), but the error still occured, do you think is somethign happend in undock?
>
>Pls help.
>
>Thank you