[Fixed] Save current sub-object selection / Groups

When using "Combine(merge mesh)" on 2 objects:-
"Save current sub-object selections" are lost.
All vertex groups on the objects are lost.
All edge groups on the objects are lost.
Polygon groups that spanned the original objects are split.

If attempting to fix the issue is a possible problem(or you think a fix is not actually needed) I would instead request command(to add to composite tool) of:-

"Delete current selected material"

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I have created 2 composite tools to "Bridge(poly/edges)" on 2 seperate objects (tools will combine/merge the 2 objects then bridge). But currently saved selection is lost when merge used. I can work around it by using a material, but no current way to delete the material(via composite tool) no longer needed/used.

What is "current selected material"?

What is "current selected material"?

The material that is currently selected in the "Materials > scene materials".
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With the composite tool, with current selected polygons, I use "Common modeling shortcut tool > New Material and Assign". That material becomes the current selected material. I can later(in the composite tool) use "Select Polygons by Material" which will select the polygons by that current active material.
I want to remove that active(currently selected) material before exiting the composite tool.
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Alternativly, make command for "Delete Unused Materials" (which is currently only accessible via material window RMB menu)

Try this
http://www.digitalfossils.com/Download/NVil-Sep-22-17.rar

The subobject groups maintained after mesh merged. The tools are added, Delete Selected Materials/Delete Unused Materials.

After mesh merge, the information of saved subobject selection becomes invalid.

Excellent, Many Thanks.