When I click F3 to display the filter box, it automatically applies the last filter, which can take a long time
Also, if I fat-finger and hit page-up or page-down instead of an arrow key, it automatically executes the filter I've paged to, which, again, can take a long time.
It would also be nice if, when I accidentally change the filter I'm working on, if I could hit ctrl-Z and get back to what I was working on.
I don't know what you do - but I tried a filter with the unchecked option for auto-apply and it worked as expected: the filter only became active once I pressed Enter.