I didn't know moving/scaling won't work with all subs, so didn't take the time to check with other video files.
With most of the others I tried now, it in fact works as it should.
Another small thing though:
I love MXPlayer's feature to play videos in the background and use it a lot.
On my old devices, MXP's space in the "pull down notification bar thingie" had an "X" to close the player without bringing it to the front again first, which was nice.
This "X" is missing now.
Is this an Android thing (old 4.42 and 4.2 vs. new 7.0) or am I missing a setting in MXP?