TATT replaces text while still in text field

[mikeevmm]

(First of all, thank you for such an useful and reliable extension!)

When using TeX All The Things in chat apps like Facebook's Messenger, the extension replaces the TeX contents while still in the text area, causing the app to delete it since it's not valid text.

My suggestion would be either not to render TeX in active text fields or to add the option to only look for and render TeX on a key press.