I discovered that the keyboard shortcuts in the subject are not working after the upgrade to 4.6 beta2 since, probably, the key mapping in Xfce 4.4.x assigned the left "Alt" key as <Meta>, while in 4.6 beta 2 it is <Alt>. Re-mapping the shortcuts solved the problem.
Created attachment 3121 Canditate to fix the issue It seems (if I understand the perl dark magic correctly) that the migration script converts all Alt occurrences to Meta, which would explain the issue.
Nick, could you please have a look when you have some time ? I don't have commit access to Xfce-Utils.
Can't we get rid of this script at all?
I don't know, do we want to support 4.4 -> 4.8 migration?
Well we can keep it for now, not a big deal. Fixed in 6003f88.