Fixed in Vuo version:
Steps causing the bug to occur:
- Create a composition (mine were simple - render a solid color layer to a window, for example)
- click stop in the toolbar
- sometimes a spinner shows up for a second or so.
How did the result differ from what you expected?:
stop shouldn't ever "beachball" - it feels unnatural. Ideally, whatever non-trivial shutdown tasks it needs to perform can be offloaded without actually showing the user.