Well, for an example - I have some surface, or a polysurface, and I want to duplicate edge… If I use _SelChain command to select edges - in a result I have duplicated edges… twice… all of them, except the one I pick first… and if this contour is something complex, with a lot of elements - it is very annoying job - to find that duplicated lines and to delete them…
Is it possible to fix??
Thank’s in advance
DV
Can you post an example file?
Can You tell me - how can I post a file in here? 
Just drag and drop it into the message window. It needs to be less than 2 Mb.
–Mitch
try to run SelChain command, to select all outer contour, and then - to
run a "duplicate edge " command… - in my case - all edges are twice
duplicated, except that one - I picked up running SelChain command
DV
example.3dm (74.4 KB)
Yeah, I see that too… Depending on which edge you pick, sometimes not all the others are duplicated… SelDup selects them.
Workarounds:
–Mitch
This one is just an simple example, usually I need to make this contour copy from polysurfaces, and running “Duplicate Border” command - will also make a lot of unnecessary geometries - exploding them, deleting unwanted, joining… a lot of extra operations… But Running DuoEdge first, then SelChain - do not allow to choose a Chain_Continuity selecting option ( position, tangency, curvature )…
It does here… DupEdge, type or hit the SelChain button, you should have all the options in the command line… No?
–Mitch
I don’t have nothing, except DupEdge option - OutputLayer…
To me it looks like SelChain is not runnig at all if DupEdge is active running command
Version 5 SR9 64-bit
(5.9.40609.20145, 2014.06.09.)
Yes. I think you are right.
[Really?] 1 What am I doing wrong, then?
–Mitch
I don’t know. I can’t figure out how you made this work at all. I have the same results as @Dimetro
The bug is you’re using the SelChain toolbar button. That appears to have a bad macro, it has a ’ in front. Doesn’t work inside SelDup. Without it it does. I typed all the commands, that’s why it works on my end. It also works if you call everything from the menus.
–Mitch
Yes. I just figured this out, too. If you just type Chain instead of SelChain after SelDup, it also works fine.