To be honest, I'm surprised it isn't the default. This is of course just a subjective opinion! For me, having tabs close and lose tab ordering and positioning is quite destructive to workflow, especially when working in projects with large numbers of files. I have to go scrolling up and down in the file browser trying to relocate something I'd opened for reference but has now closed again. The behaviour feels rather arbitrary / random too; the threshold depends on window dimensions, so it isn't very user-predictable. I never remember to right-click and choose "Sticky"; it's not something I've ever had to do in any other text editor or IDE, so it's just not in my muscle memory.