Comment # 1 on bug 1064546 from Wolfgang Rosenauer

I guess that is the configuration
layout.word_select.stop_at_punctuation
Please use about:config to switch that flag and see if it behaves as you like
it.

We indeed change this behaviour from default to "false" in our installations.
If I remember correctly the last 15 years we changed this once and people
complained and changed it back. I cannot find a reference anymore though.

Anyway I reconsider it to change it for future versions if you confirm that
this is the behaviour you are looking for.