# Key Up events not ALWAYS registered (only when in FireFox)

**URL:** <https://forum.kirupa.com/t/key-up-events-not-always-registered-only-when-in-firefox/330783>\
**Category:** flash\
**Created:** [March 14, 2013, 11:30pm UTC](https://forum.kirupa.com/t/key-up-events-not-always-registered-only-when-in-firefox/330783 "2013-03-14T23:30:10Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![GBurg](https://avatars.discourse-cdn.com/v4/letter/g/e495f1/32.png) [@GBurg](https://forum.kirupa.com/u/GBurg)\
**Post date:** [March 14, 2013, 11:30pm UTC](https://forum.kirupa.com/t/key-up-events-not-always-registered-only-when-in-firefox/330783/1 "2013-03-14T23:30:10Z")

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Hi guys,

Although this is strictly not an AS3 problem, but more a browser problem. It is a problem I am having recently, and would gladly want to have a solution for. I noticed that in Firefox, my Key Up events are not ALWAYS captured, but sometimes they seem to be lost/undetected.  
I was wondering how this could be possible? It only happens with the flash plugin in Firefox (not in Chrome/IE). I have only vague ideas, like it is skipped when a frame has run for too long, or something like that…? Can that be true and can key up events be lost?

Best regards,

Geert

PS. I never have this problem (lost events) with key down events. Can these two events be in competition with each other? Like when you press down a key for a long time, it will eventually do D…DDDDDDDDDDDDDDDDDD . Here D means Key down and it is on some sort of timeline. Might it be possible that it ads another down, just after the up, so than it would become: D…DDDDDDDDDDDDDDDDDDUD ??