As with normal mesh manipulation via the Blender Python API, when using the BMesh object to deselect vertices, it is not enough to simply change the value of their “select” property to the opposite. To deselect the vertices of the BMesh object, the “select” value must also be changed for the edges and polygons adjacent to them.
Copying objects to the clipboard is used in Blender in the same way as in all other applications: by pressing the Ctrl + c key combination, and pasting from the clipboard with Ctrl + v. However, an interesting feature of copying and pasting objects in Blender is that the system clipboard is not actually used.
Commonly, when a user executes an operator in Blender, this event is automatically recorded in the “Undo History” list so that in the future he can quickly undo the execution of the operator (Ctrl + z) or execute it again – redo the operator execution (Ctrl + shift + z). However, this does not always work.