Macbook & Studio Display: How to avoid clamshell mode, when closing the lid?

This is really annoying, I wanna use both screens - Macbook and Studio Display. When I finish work and close the lid, there's no way to avoid the clamshell mode. If you click on standbye, it turns off, but if the mouse is touched in the slightest, the Display goes on immediately naturally.

The problem is that the thunderbolt cable to connect the display with the macbook is also powering the macbook. When I had the thunderbolt display with the usb-c adapter I didn't have the issue because the powering came from the magsafe alone, so I could control it and hence avoid the clamshell mode.

I don't want to unplugg the display each time I close the lid. This is ridiculus. Why is there no option to simply disable the **** clamshell mode. Do I really need homebrew to change the code manually?