In the new snapshot 13w01a, the game crashes when you drag blocks one by one in creative mode IF you drag it into the Survival Inventory Page.

Test it: Go into Creative Mode and click any item or block, just one. Hold-click it and drag it to place it in the hotbar then drag it to the Survival Inventory Tab. Let go of click to enter Survival Inventory. Click once to place item in inventory. CRASH!