Can anyone tell me how to stop a “plusone.google.com” tab from opening randomly in Firefox as I read my Google Reader?
Click on your avatar (your pic) then select Account Preferences (it may be account something else, mine is in Swedish so translating.
Then click on Google+
Scroll down to Google+1 and click on Edit.
Select Inactivate then Save.
Close that page and test.
It might have helped, thanks :)
Is there any other way not using any plugins?
Maybe try changing the pop-up blocker settings in Firefox? Or you could also try adding the "Adblock Plus popup" add-on to your browser and add plusone.google.com to the list of blocked pop-ups by editing the list.
I tried the pop-up blocker but you can only allow and not block. I'll try Adblock as a last result. Thanks :)