Regarding double-clicking the timeline graph, I can see how that would be useful to the experienced user. However, to a new or casual user, this could easily look like a problem in the software. They might think they broke it and become confused/upset, etc.

Hell, *I* thought it was a bug. :-)

This might be one of those cases where we could use an alert box that pops up upon double-clicking the timeline graph, briefly describing what that functionality is for and how to return to normal operation...accompanied by a "Do not show this in the future" checkbox.

I just feel that this is too easy to trigger and it's not obvious what the purpose is or how to undo it.