start working on #100 and had see interesting behaviour. I think that as CodeEditor based on TextBox so he, on idea, must use handlers from there, in this case Backspace. But changes in Backspace function didn't change work of CodeEditor.
Why it happened and where corresponding function for CodeEditor? I didn't found any appropriate methods.
I pulled all of that out into an input.Handler type both to reduce our reliance on gxui and to allow the behavior to be overridden (for example, one of my friends wants to write a vim-style input handler to override the default one)