The emulator is already running, but not able to see it in ubuntu

Question

I use ubuntu 12.04 and Eclipse Platform Version: 3.7.2, I have one problem that I sometimes observed on my system. I do not know if this problem is common and did not find any related issue. is - "when I tried to launch an Android application using the emulator (API level 17 Nexus 4), it works fine, the problem does not occur, and the emulator is in front of me, But the moment I open another window, for example, the browser, it hides it editor, and I'm not able to see it. " The magazine says the emulator swears, but does not know where it is hiding.