I much prefer switching between apps by using the keyboard shortcut Alt-tab. However, for some reason it's been a bit buggy of late.

About 1/2 the time, it will do nothing and then if I hold down Alt-Tab for about 4 full seconds, it pops up, scrolling through the windows. This doesn't always fix it though. The problem can persist and the only way to get it to work at all is hold it down for 4-5 seconds and then scroll through.

Sometimes, though it will just start working again!

It's not always the same apps either. Sometimes "alt-tab"-ing between my browser and my text-editor will work and sometimes it won't. There doesn't seem to be rhyme or reason to it.

How do I debug/fix this?