Sometimes `_highlight_cword` is called without the existence of
w:cword_timer_id but with a w:cword_match_id. No idea why.
I thought that it might be a race condition, but does not seem like it.
(Also not sure if this could even run in parallel)
TODO: Investigate how _highlight_cword can be called without
w:cword_timer_id
Julian Prein
2322f4ad67
