Game properties break when pre-positioning pieces I have a game with a 3D board and game pieces. I have the board divided into tiles. When a player clicks on a piece and then a tile, the piece moves there. Right now, it's under construction, so the early primative pieces are floating around in space. All attempts to position the pieces in a starting set up, (this includes positioning by hand, and using the shift-s 'snap to'their  feature,) result in the tiles and pieces losing properties. I cannot select a piece, nor can I select a tile. The rotation of the board still works though.

If it helps to visualize, I made a shot video of my progress for my friends: https://www.youtube.com/watch?v=hwFA1MlgZGY
You have accidentally hit this button:

Which has disabled the manipulator. Not sure if that is the problem you are describing? Note that even with it disabled you can use the shortcut keys 'G' 'R' 'S' for grab, rotate and scale.

I have never heard of moving a piece removing it's game properties though.