When writing a muse file it always annoyed me when I have written (for example) a-really-long-variable somewhere else in the file and then when I type =a-rea and press M-/ it fails to expand.

The way to fix this behaviour is by setting dabbrev-abbrev-skip-leading-regexp

(setq dabbrev-abbrev-skip-leading-regexp "[=*]" )

(Edit: fixed the first regex per Billy’s comment below. Thanks)

Okay, you think, this doesn’t affect me – I don’t use muse (why not?) How about if you’re writing some html/xml.

(setq dabbrev-abbrev-skip-leading-regexp "[ ^ ]*[<>=*]" )

Now <strong>long-word- completes as you would expect.

There is also dabbrev-abbrev-char-regexp if you want even more control over what should be considered a match.

Also, I’m no longer using autocomplete as I find vanilla dabbrev nicer to use.