Does that mean you are the second person this week I enlightened in this regard? (or did you find out in-game..)
I used Shift-click with my stacks of crafting materials frequently, but it never occurred me that I could use it for Commendations, too.
However, when I tried it yesterday, I indeed got stacks - but there was something I did wrong, because I didn't seem to get the stack I had chosen.
Is there any additional mouse click or movement required ?
Usually, when I choose stacks of crafting materials from my inventory, I shift + right-click them, and then I'm presented a small dialog box which lets me choose a number ... and with a click on the button of that tiny dialog box, and then a right-click into my inventory, I get 2 stacks from 1.
This didn't seem to work when I tried to get stacks of planetary Commendations, though.
I tried this procedure, but somehow the stack wasn't transferred into my inventory ?