I have Ubuntu 14.04 installed on my PC with 2+ Ghz processing speeds and 4gb RAM. While I'm browsing on using Firefox, the browser suddenly gets dim and then bright. It happened multiple times. While it happens, I cannot open a new tab or close the existing ones(to say, the browser freezes). Is it a problem with the software or with my PC ? Did anyone face similar problem ?
Try resetting Firefox...
Try the links given below.
Reset Firefox to its default state
Firefox Slow/Hangs
Relax, This is a feature in ubuntu. Everytime your comp becomes unresponsive, it dims ( becomes greyish in colour).
Try not opening many tabs that are active. This should reduce the load on the cpu. Try removing any extra add-ons in the preference menu if any.
I presonally experience the same while launching ADT(eclipse) for a brief 2 or 3 seconds but is goes away after that.
Also, update firefox and other packages. run the following in the terminal: