The command is used to join two panels at an angle (Miter corner).
To open the command, go to:
Skeleton Dress Up –> Miter 
Select first panel – the first panel is selected. Once the panel has been selected, the program automatically goes to the selection of the second panel.
Select second panel – the second panel is selected.
Mitering trim depends on the point at which the cursor was placed when selecting the panel.
Joining panels at a slanting angle depending on the position of the cursor
In cases where panels of different thickness meet at a blunt angle, the panels will not be correctly joined at a slanting angle.
Incorrect alignment of panels of different thickness joined at a blunt angle
In this case, use the "Direct Edit" command to extend the thicker panel and trim it.
Alignment of panels of different thickness joined at a blunt angle after extending the thicker panel