Extract from how to report bugs
lease only test the latest version of Construct 2
Often bugs are reported which have already been fixed. Please make sure the problem occurs on the latest release.
Also are you sure that the F5 key doesn't work for sure ?
I mean, it happens sometimes that the browser doesn't get the focus and stays under C2, but in the tab where my game is executed, the game is actually "updated".
It can happen if the tab where you first previewed your game wasn't closed.