[editing] What to do with IME input when typing over a large selection? (#59)

Imagine this:

```
<div contentEditable="typing">
  <p>This is a test <span>t[ext</span></p>
  <p>This is a <b>secon]d paragraph</b></p>
</div>
```

The []-symbols mark the start and the end of a selection. With this selection in place, the user now starts creating new input using IME. What do we do?

We specifically tried to avoid for the UA to do paragraph merging or any changes to the DOM-structure. and the IME added characters will only create a beforeInput (intention) event, not an actual insertion by default. 

Solutions I can see:

A) If the IME is to overwrite anything beyond the contents of a simple text node, the composition process is not done inline but rather in a little box next to the text.
B) We first emit a beforeInput delete event, then start the composition process.
C) IME handling is moved further to Javascript.

I vote for B.

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Reply to this email directly or view it on GitHub:
https://github.com/w3c/editing/issues/59