You can test this bug with any Office 2007 ribbon toolbar application using NetAdvantage 2008 vol.2 on Windows XP (this is not happen on Windows Vista).
When you maximize your form, then click a button to open a dialog box, or just activate other application and activate your form again, then you will see that the form improperty redraw itself and cause size changed for controls insize it. It's so messy, please fix this bug soon.
I applied the Hotfix 2008.2.2022 and the flickering problem seems to be solved.
I would like to add that I'm experiencing the very same behaviour.
I am seeing the same problem with my application. This only happens when the form is maximized. If the form's windows state is normal, the refresh/redraw doesn't seem to occur.
You should Submit an incident to Infragistics Developer Support.