We're making some significant changes in the frame management is done in Tecplot 360/Focus 2009, the release that is planned for early next year. End-users should be very happy with the change; however, there has been some concern that this may affect add-on behavior in ways we hadn't anticipated, particularly add-ons that use more than one frame. We'll have a working prototype by the end of October and would like to get some feedback on it.
Conceptually, the behavior change is to let the "active" frame not necessarily be the topmost one. This is different from the current behavior where the active frame is always the topmost and making a frame active "pops" it to the front.