While working on a multi-pass polargraph drawing over the weekend, I ran into an issue that has popped up occasionally in the past. After a drawing is finished I clear the image, load a new one, hit "render pixels", the pop-up dialog appears, hit the button that generates commands, and.....nothing. No commands are sent to the queue, and seemingly no button does anything (except mouseovers do display, if I remember correctly).
Since I'm doing multiple passes, I really want the registration of passes to be spot on, and that's easiest to achieve if all the passes are done during the same controller session. So, is it known what causes this to occasionally happen, and is there a way to avoid it?
Here's the pic, BTW:

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