How to show code window full screen next to Groups and Files

Xcode seems to split 开发者_运维百科the code window and show the file name in the top segment and then the code in the bottom segment. Does anyone know how to set it permanently so that that only the code window is shown on the right and then Groups and Files on the left

Shift+Command+E hides the top segment. The state of the window will be remembered, so it is kind of permanently.