I understood your problem. So far, the reason why this happens has not been identified. Try checking the key assignments, press Escape, open the settings in the Controls section. And also try to delete the door using the console, to do this, point to the door, press F2 and enter "remove forward" in the field below, then the door will be deleted. I also added a new version with debugging in the console, this may help with solving your problem.
Something strange is happening to you, since everything works for me.
Chairs and other objects, except keys, can be dragged by holding down the left mouse button!