Pop up Menu

Hello Everyone.
I had a small doubt regarding the pop up menus.
I observed that the display callback is invoked when the pop up menu disappears.But this happens only once.

It must happen everytime the popped up menu disappears right??
I mean should’nt the display fuction be invoked evertime the menu disappears ,in order to redraw the window?

Can anyone please explain?
Thanks in advamce.

Are You talking about pop up menus of Your window manager?

If so, I guess that depends on the WM.

I believe the behaviour might be different in KDE and Gnome, Java’s swing pop ups, using JOGL, might have also different behaviour (I’ve noticed that GLCanvas and GLPanel are exactly different in that regard) and of course Windows might behave in it’s own way and make the redraw callback (or not).

Thanks for the reply.

So you mean to say its the windowing system that decides when the redraw has to be called back and not by OpenGL?

For eg. can i have a windowing system that does no provide a redraw callback even when i reshape? so does OpenGL not deal with this aspect?