The creative mode inventory is not properly showing all the items. You are unable to see all the available items and blocks. But they are still there. I am hoping too see a new custom creative inv with scrolling features to pick an items. In the first screenshoot you can see how the inventory is, there is a list of stuff you can choose. But there is more bellow witch is impossible to see. So you just need to quess whats there. In the second screenshoot there is a creative inventory that you can scroll. I made it myself and i would love to see that type of inventory with scrolling.