First of all...thank you for your help and your time...

Also...
- i tried to SetMaxSize,SetMinSize,SetSize in wxSmith resource(with integers of course)...
- and i tried in constructor of my scrollingdialog to call SetMaxSize(wxSize(-1,700)).
But i receive the same error.
I use a release-build of wxwidgets.
I can ignore the message...and the scrollingDialog is resized...
but i suppose that in definitive version of my .exe file i receive the alert too.
And that's my problem...because i can resize..(but i receive the alert)...

if you would i can send you my .h/.cpp files.