The current RMB menu for the stars plugin should be changed to the following text and layout:

[x] Show Constellations

[x] Show Sun and Moon

[x] Show Planets

[x] Show Deep Sky Objects

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Configure ...

All RMB entries should refer to the actual objects AND labels. So checking one entry should enable  objects AND labels in the RMB menu. Deselecting an object should disable objects AND labels. No new member variables should be introduced - instead the existing ones for objects and labels should be synchronized. The state of the entries should be in sync with the respective settings dialog entries. If in the settings dialog only labels are not deactivated for the correspondig object then the checkmark in the RMB menu should appear gray. This gray tristate should not be accessible through clicking on the RMB menu.