Board Thread:Support Requests - Getting Started/@comment-28408407-20190525113435

I'm trying to edit one of the pages on my wikia. I clicked between two of the letters, but instead of doing what it normally does, it highlighted one letter, as seen in the picture: And when I try doing backspace, it starts erasing everything behind that letter in some kind of weird way, it's hard to describe. How do I fix this?

EDIT: it does it on every page on my wikia and in source mode too. It's not doing it in this forum post, though, and it doesn't do it on non-wiki pages like Google, so it's not a problem with my computer. 