I work with book layouts and sometimes will accidentally type in a letter into the already written text while formatting it. Most times I noticed and undo it, but here and then a mistake may go unnoticed and risk having that typo printed.
It would be interesting to rely on a feature that allows me to easily disable and enable writting.
For instance, when the box is marked, I can still edit size, color, all that, but can no longer add or delete any text.
When it's unmarked, it works as usual.
Another option would be a "popup" that shows more clearly than the "history" section when I have typed in a new text.