This is more a list of issues I don't like on that tool, but whatever:
* It isn't possible to comment a task without marking it in some way. E.g. it would be helpful if others already experienced lacking Aerial Imagery.
* When you take a task which is marked as "done" you can either validate, invalidate or unlock it. No possibility to mark it as "done" again, when you just added some more stuff. Chose "unlock" then
* To mark a task as undone you have to click "validate" and then "invalidate". NOT straightforward.
* When you mark a task either way (done, valid, invalid) there will always be an comment with your nick on it - empty, if you didn't enter anything
* I'd welcome a more homogeneous interface. Why does "unlock" have to be a link not a button? As it is now you oversee it easily.