What version/edition of TC?
From V12 through V16 the "Flip" commands will become available in the Local Menu and Inspector Bar when you select a Door/Window with the "Edit Tool", not the "Select" tool. In Version 16 they added the flip feature to the Local Menu and Inspector Bar when inserting a Door/Window.
Designer, Deluxe, Expert, Basic, Platinum
Windows 10 Pro, 64-bit