This functionality is already implemented in the whisker menu and it would be good to have it also in the right-click context of launcher entries in the panel.
I see that Simon stated "The launcher plugin will receive a feature from garcon, i.e. showing the Desktop Actions of a launcher item in its right-click menu (i.e. “Open Private Window” for Firefox). This is really just a feature preview though, the code is in working but very hacky/rough state." [1] From the image shown on the page of this feature, I would recommend that the 'move' entry be moved above 'remove' and a separator added before it, so it looks like so. Launcher - separator - Properties Open a New Window Open a New Private Window - separator - Move Remove - separator - Panel > [1] https://simon.shimmerproject.org/2019/10/19/xfce-4-15-development-phase-starting/
The launcher will surely receive this feature for 16.04, I have already pushed the general feature that is necessary to achieve this to garcon. Re-ordering the menu would affect all plugins (all plugins currently use the same context menu) - plus this is a separate bugreport/feature request in my opinion.
Okay filed it separately - bug 16491
Fixed in https://git.xfce.org/xfce/xfce4-panel/commit/?id=7f3dd44de951a74dc1adb446e2b2f643043b1100