Seven times out of ten when I click on the “EventGraph” after having been inside another function graph the “EventGraph” snaps to my cursor and become stuck, and I am aware you can move the tabs, by click dragging, but that is not what i did, I released the mouse button with the tab still stuck under my cursor.
Since you were able to get around the issue, I am marking this as answered. Please let us know if it occurs again and we will be happy to further assist.