I'm seeing a weird problem in this case:

1. Start with a paragraph: `<p></p>`
2. Place cursor between the open and closing tags and type "&"
3. The entity hint list is displayed as expected
4. Press Esc to dismiss list
5. Press Ctrl-space to re-invoke the hints list

Results:
Hints list is displayed, but it's a list of HTML Tags!

It might have something to do with using a priority of 0 to register these hints, which is the default priority. On the other hand, there should be no conflicts with the HTML hints, so not really sure.