This got stuck on my screen when i was fighting around a tower. It didn't cause any issues other than be on the screen and annoying.
Thanks for the report! This is a bug with our "smart ping" system. As a workaround, you can do another smart ping, and the menu should go away. We're looking into the bug, but haven't figured it out yet.
(You can smart ping by pressing "g", click and hold on the spot you want to ping, then dragging the mouse to one of the four symbols)