unable to highlight several words and type over them (1 Viewer)

[Frank The Rat]

for some reason if I try to highlight several words, then type over(trying to replace those words) it does not delete the words, it just adds the words that I type into to document. This just started. Anyone know how to fix this issue.

 

[RazorOye]

your Insert key - toggle it

edit: if that doesn't work, just restart - probably just a fluke - is it doing it in all text edit programs you are running (forums, Word, etc....)?