Creating a whole new version of the app would be a *lot* of work, but we have definitely noticed this happening as folks learn the app, and it's something we think about a lot. Ideally, we can find ways to make the app easier to learn without removing features that folks may value once they've gotten their feet under them.
Off the top of my head, I can think of a couple changes that we could make which might have helped. sgraff, your thoughts are particularly valuable here, since you're a prime example of the kind of person we'd like to help. Suggestions from anyone are welcome, of course.
Random, barely-formed ideas:
1) We could start the app off in "All Projects"/"All Actions" mode.
Advantage: nothing would disappear, preventing unwelcome surprises. With any luck, folks would naturally be lead to the "how do I hide the done stuff" question and learn how the filters work at that point.
Disadvantage: Nothing would disappear, including completed actions/projects. I fear for the folks that didn't learn how the filters worked, and doubt they would use the app for very long. :-)
2) We could add an "Undo" button to the toolbar - it's a feature that's always there, but I think the experience of having stuff disappear from view is sufficiently disorienting that folks forget about it.
Advantage: A visible reminder of the feature might help folks.
Disadvantage: Feels clunky - my gut tells me there has to be a more elegant solution.
In any case, good food for thought here - if folks have any suggestions, we are really open to suggestions.