One thing I don't like in the Dev module is when the mask panel is opened with no mask selected, it's still possible to move the sliders (exposition etc.) but without any effect on the image.
I would much prefer to have the entire Dev tools available for global adjustments (despite the masks panel opened) OR a warning: "please select a mask" OR all the Dev sliders greyed out.
I find the present configuration pretty confusing and not consistent.