I just implemented a new FormReady event for visual designer forms. I can't believe that I hadn't done this sooner. Over the years there have been many posts whereby you want to do something (like setting focus to a control, or popping up a login screen) but you need the main form to be fully loaded first. The posted solutions always involved using PostMessage in the WM_CREATE or Form Load event to post a custom message to the Form. You then handle that custom message knowing that the Form is now fully ready for user interaction.
The above process has now been all integrated into the visual designer via a new event call FormReady. This new functionality will be in update 2.1.4.