VS add-in solution explorer context menu group
CommandPlacement usage to have the same menu item for several different add-in menus
To duplicate the same group with submenu items I removed the parent element from the grpIdMenuProjectItem group declaration
<Group guid="guidCmdSet" id="grpIdMenuProjectItem" priority="0x0700">
</Group>
and have added three command placements for item, project and folder parents
<CommandPlacements>
<CommandPlacement guid="guidCmdSet" id="grpIdMenuProjectItem" priority="0xF00">
<Parent guid="guidSHLMainMenu" id="IDM_VS_CTXT_ITEMNODE" />
</CommandPlacement>
<CommandPlacement guid="guidCmdSet" id="grpIdMenuProjectItem" priority="0xF00">
<Parent guid="guidSHLMainMenu" id="IDM_VS_CTXT_PROJNODE" />
</CommandPlacement>
<CommandPlacement guid="guidCmdSet" id="grpIdMenuProjectItem" priority="0xF00">
<Parent guid="guidSHLMainMenu" id="IDM_VS_CTXT_FOLDERNODE" />
</CommandPlacement>
</CommandPlacements>
The CommandPlacements node should be added after the Commands node as documented.