I am also having this issue but mine has not gone away. I also use a lot of external monitors, projectors, Promethean products. Sounds like we are both in a school environment. A little more info on my issue is that it happens at any time in many programs. Yours was just in a browser? when the box comes up I cannot type and it also manifests when i scroll in a document i am creating and it highlights everything yellow as if i am about to copy a portion of text. I then move the cursor and it highlights as i go and i try to press esc to make it go away. It gets so bad at times that i just give up and walk away. I am about ready to reimage my machine.😕
Does anyone know what this could be?
