Some articulations/ornaments can be flipped with "X", others not
(That's in some way a continuation of http://musescore.org/en/node/291 )
Some articulations/ornaments can be flipped with "X": the symbol is put upside down and moved to the other side of the note.
In others, only the symbol is put upside down, but there's no change of side.
Sometimes, there are crashes.
-->>So the thing is that there's a code that can do this fine, but it hasn't been copied to all the ornaments.