Moving notes by a tuplet

Hi, I was wondering how I can move the selected note to the left by one eighth note triplet. I thought it would work by selecting only the notes without the triplet mark, and use the alt-cmd-← shortcut. However, if the chord mode (Q) is not activated, the tuplets are cancelled. If the chord mode is activated, it does something quite weird ose you can see in the second screenshot.
Thanks for your help!

That is odd, but I suspect it is because the triplet is somehow connected to the first eighth of each triplet and displacing that first note of each triplet (with ATL+LeftArrow) clears the triplet.

Activating Chord mode keeps the triplets but does not move all the notes where they are supposed to be.