PM- I thank you for the correction.The Rosh, indeed, differs from tosefos and maintaisn it is kibui when you take oil from a light. He refers to the gemoro shabbos 29-2. “lo jikov odom shafoferes’ and the sugya there. From rashi (and the rosh’s understanding) they hold that by taking some oil from that container that supplies the oil would be mechabeh. in truth , this is a very tough shittah to undersatnd because the “kli” that contains the oil is suspended above the “ner’ and has no contact with the light. I fail to undersatnd how thsi could be, in any way,kibui.
And, indeed, I refer you to the Rambam (Hilchos shabbos 6, mishne 12) who gives a different reason for that mishne (mukzoh) and the lechem mishneh there, who clearly writes that the rambam holds this is not ‘mechabeh” because the oil is NOT in the actual “kli’ that is burning.
Clearly, there are various shittos and , in our case, this being gas that has molecules that are not bound together, makes it even more problematic to ascertain that it is absolutely “kibbui”.
It is a lot more complicated rthan it looks at first blush. there are even gemoros that contradict each other on that and certainly the poskim have many different approachs on this.