I think features such lightmapping and others, should be done in a children windows, as separate process, nothing to do with editor, so one do not affect the others, as well, GG is a MDI app.
If you want bake your escene, simply GG open another windows to LM your scene, with all the necessary tools there.
Of course LM should be done windomized, nor full screee, and being able to work minimized, maybe in a memory cache, or something like that; so, you can work with editor meantime, F4 can takes longtime.
So, there also store both versions, Realtime and Bake one, working like "LMbank".
Just my thoughts.
3com
Laptop: Lenovo - Intel(R) Celeron(R) CPU 1005M @ 1.90GHz
OS: Windows 10 (64) - Ram: 4 gb - Hd: 283 gb - Video card: Intel(R) HD Graphics