Middle Mouse Button icon
Hello, please excuse my English...not my native language and not my strong side.
I'm having this icon of the middle mouse button, shown at the right edge of my browser and the scroll doesn't work when it is shown. It's like there is a hidden panel at that side. I don't remember exactly when did this occurred, but it bothers me and i would like to get rid of it.
Thanks for your time, really appreciate it.
Here's a screen of it: