Yes I was looking for the copy button in the Custom Layout the other week.
But to come back to what Sean was saying.
I might have a customer who says that they want a display cabinet on either side of the range hood (actually more often it is me the designer who says that this would look the best).
This is the flip or perhaps mirroring button I was also looking for.
If it is just a copy and paste button, I think you still have to go back into the Custom Editor and change the doors and handles to the opposite side (for single door units).
Which is no real big deal, but if you are looking at streamlining and user friendliness this is one of the features I would add 
.
The other uses I can think of are left and right hand corner units with mirrored doors or end sizes in the corners.

- This is a Cnr unit with different size ends but often asymetricl doors are used
- 400x300 end.jpg (37.63 KiB) Viewed 13740 times
Blind corner units, (saves you working out sizes of reveals and if you have added panels and fills to turn it into an assembly it saves you heaps of time.

- This is an assembly with 3 parts, So in the cab editor you have a few "Align to zeros" and some part rotations. A copy/mirror would alsobe very useful when I need it again.
Resizing ends or widths for this is a pain, but thats an other post. LOL (Or I will find another layer to ecabs that I havent discovered yet) - Blind cnr.jpg (32.07 KiB) Viewed 13740 times
And quite a lot of entertainment units are mirrored around the screen.

- This one has symetrical part editor cutouts in the end units. A copy/mirror would have been very useful.
(While I don’t have a machine, I am evaluating the practicalities and time savings that I would get if I were to purchase one.) - Viki Danny3.jpg (80.52 KiB) Viewed 13740 times
A simple highlight of 2,4 or more cabinets and mirror left and right would have saved heaps of time on the above job
Left and right open shelf units or cabinets left and right of windows.
These are some of the times Copy and mirror buttons would have been very useful on actual jobs for me, I,m sure that many more examples could be found by other users.
I think if there were Copy and mirror buttons they would become quite indispensible.
