Bit of a weird one. Two monitors set up in extended display. If you run construct 2 on monitor 1, right click a sprite and select "edit animation" the window opens on monitor 2. Fine. If you then switch to one monitor, the "edit animation" window will still open on monitor 2. You won't be able to select the window, close the window, save your work or quit. A re install won't fix this, somehow your window location presets are saved. You have to get out both monitors and fix from there. Not a bug, just an annoyance and probably a simple fix.
Go fight win.