The project tab has essentially two columns. The left column (Active Project/Build and Run/Project settings) on a large screen can be 2000 or 3000 pixels wide. This is too much and makes difficult to use. The layout must have been set to expanding when it should have a maximum width set, say 300 or 400 pixels. Make sure the right hand column doesn't expand too when you fix the left hand column.
A picture of the problem is attached.