I suspect the wanted feature is something to simplify the 2 first steps from following:
1. Open XML editor
2. Select layer group from there, <g:layer id="layer1"> for example
3. Copy
4. Paste
IMHO it would be really rare used feature and would only clutter up the useful UI space. If in Edit menu, you even wouldn't spare any mouseclicks. Only way to spare a click would be to have modifier for icons and/or for Ctrl+C shortcut.
I suspect the wanted feature is something to simplify the 2 first steps from following:
1. Open XML editor
2. Select layer group from there, <g:layer id="layer1"> for example
3. Copy
4. Paste
IMHO it would be really rare used feature and would only clutter up the useful UI space. If in Edit menu, you even wouldn't spare any mouseclicks. Only way to spare a click would be to have modifier for icons and/or for Ctrl+C shortcut.