strange behaviour with Thunderbird

[Joop]

Fresh start, FF31.8.0 some youtube stuff, close FF, start TB, euhh? just 150Mb max! instead of up to over 900Mb. Close TB, start FF24.8.1 some youtube stuff, close FF, start TB, still 150Mb max. Will try next time first FF24.81, then TB and see what happens. For the record, I didn't change a thing.

[Joop]

Fresh start this morning with FF24.8.1. So the libs for that program are loaded. Closed FF and did start TB. Again just 150Mb instead of 900Mb. I didn't change a thing on setup, but I do remember that I had thrown out a membership on a newsgroup with not so many messages and I deleted the newsagent too. Probably this was on a fixed position in the database(?) which now freed up space(?). Anyway, if it stays this way with only 150Mb I'm happy.