track not disappearing from screen

Sorry to ask if this has been covered before, but when I make an error of track laying on the screen and go to project to delete it, it doesn't disappear from the screen, and it is difficult to move it out the way.
Also the same with cut, double clicking and pressing delete.

I am using a work PC so that might be it
but help...
Thank you in advance
Stewart

Managed to work out what was going on... Because I hadn't saved it first the stuff wasn't disappearing when I clicked delete...
Even if there is wrong stuff on there, then save it, download or again and the tracks are deleted..
Hope this helps newbies

Stewart