Beware: This might be a Hunspell issue.
I would like to have words like this in my user dict:
oil capacity and grade
Ölmenge und -qualität
A typical German problem: We use the hyphen to avoid repetitions (I could also have set "Ölmenge und Ölqualität", but this is ugly.
It would be nice and make sense to have "-qualität" in my user dict and have it work (I can add it, but it does not work), as only "qualität" without hyphen is a mistake. So Hunspell could differentiate these two cases.
Is my problem clear?