Programs suddenly disappear

[umarzuki]

I'm using Cassandra and Deluge and Firefox suddenly disappear after I left my PC for a couple of minutes. Any possible problem that could've triggered by me without my own knowledge. I just installed a couple of programs like WoP, OpenArena, Frozen Bubble, VMWare, and a couple of others.

[Husse]

What do you mean with disappear - it's completely closed down or disappeared from the panel or...

[umarzuki]

it dissappeared from the panel, but still available in menu.

[Husse]

Is firefox still running after it disappears from the panel?
This is a completely different error from a total shutdown when it's not running so I want to know which before I try to find a solution

[umarzuki]

Well, I can click on Firefox's quick launch icon on the panel and it work perfectly. It usually happens to Deluge rather than Firefox which I only encountered once opposed to almost everyday situation with Deluge.