How to remove an attribute?

[karroze]

I have a custom attribute to support mentions functionality. This works fine. Now I need to implement a feature where removing last character of mention text should remove whole mention all-together.

I'm trying to do it by using this:

_controller
  ..replaceText(
    startIndex,
    endIndex,
    '',
    TextSelection.collapsed(offset: startIndex),
  )

That removes my attribute from Delta document, but as soon as I start typing again this attribute comes back with the first letter of what I've typed.

Am I missing something? Why after document having no inserts with any attributes it magically comes back again?