I wanted to extend my application to also use different browser. So I start using GeckoFX 45, but after some digging I noticed that Mozilla stopped development of XulRunner, so basically if my understanding is correct it does no have sense to invest in GeckoFX 45 as there will not be other version and I want to use as latest version as possible. Is GeckoFX project affected by stopped development of xulrunner as I think ? Is there any other alternative ?
Geckofx uses libxul which is part of Firefox. From my perspective (which may not be nuanced enough) libxul is essentially the gecko engine.
Firefox.exe -> xul.dll
In the past
xulrunner.exe -> xul.dll
existed and was supported.
geckofx -> xul.dll
Geckofx development isn't in itself affected by the stopping developing of xulrunner. Although it possible that there could be some negative consequences that makes Geckofx development harder due to there being one less user of xul.dll.
As for XUL (the UI specification) itself Firefox internally still uses XUL , although I guess it is unlikely that the XUL spec will get any further development.