In the What's New 2016 Pre-Release 1 Dokument on page 27 - Keyboard Input in PropertyManager
I was able to confirm that the TAB moved the selection from control to control. Although not mentioned that Shift-TAB moved us back upwards.
The "spacebar" toggled the selection, where a box is activated or not. And Arrows up or down Change the selection of items controlled by Bullet Point selection.
However this dokument stated "Use Keyboard shortcuts to expand and collapse Group boxes", but doesn't specifically mention what those shortcuts are.
I could not find this in the UI Video, or in the help Topics. I also checked the list of Items for "Keyboard shortcuts" to see if I could define this. But I couldn't find it there either.
Maybe someone can give me a hint, either what those keys are or where to find Information about them.