I had this annoying problem in Chromium. I have to mention, my OS is Elementary OS Freya 0.3.2. So everytime I hit CTRL + T to make a new tab, Developer Tools was popping up in a new window. I googled for a solution but I haven't found anything. I even tried to reinstal Chromium. And after a while it came me this idea:
I remembered that since the last update I haven't restarted my computer so I restarted the OS and guess what? This solved my problem.
