After using Firefox for some time (from 10 to 20 minutes, usually), it simply refuses to open any new tabs, while all that were open previously continue to work normally. Click on "+" sign next to the last open tab simply produces no reaction, and the same is with "Open Link in the New Tab" command from the right-click menu. When restarted, problem disappears, just to reoccur a few minutes latter. This has started to happen about a month ago, all of the sudden. Has anyone experienced something similar? I'm on Win7, using the latest version of Firefox. I have tried to start Firefox with all the plug-ins disabled - nothing has changed. Thanks in advance!