The problem is: it initializes OK, and works, you can resize it, etc, but you cannot do a form borderstyle change. It seems the connection between the form canvas and the OpenGL is then lost while OpenGL still works reporting valid execution times in the memo1. Maybe in this case I should close all OpenGL stuff, clean up and initialize it again. Or maybe a form create event is called when the border style is changed which causes reinitializing OpenGL... Now I have some ideas to try.
Edit: worked around.
Before border size change, openglcontrol1.destroy;
After the change, recreate it and reinit opengl.
Ugly, but works.