In my application when I click and hold down on a NSButton it stops the NSTimer loop that calls my drawRect. And I'm wondering why that is so, and how to prevent it. I tried making my own subclass of NSButtonCell and overriding trackMouse:inRectfView:untilMouseUp: and the other subsequent tracking method associated with it. But that didn't help, though I still assume there's something in there I can do to prevent this. I also tried running OpenGL on another thread but it still seems to get blocked when I hold down the button.