I believe blacklisting fields in specific contexts would be a nice and useful addition.
My use case: I have a DokuWiki site on which the move plugin is installed. This adds a Rename page menu option, which executes some JavaScript that opens a pop-up window to ask for the new page name.
The problem is that Kee thinks that the input field is a username (it is defined like <input name='id' ...>) and overwrites the field’s contents (which defaults to the current page’s name with path, as shown in the pop-up’s title. Incidentally, that can’t easily be copy/pasted due to a JavaScript event to move the pop-up around).
I suggest to add an option in Kee’s context menu to ignore the entry (temporarily or permanently), and restore the input field’s initial contents.