suggestion: - when you merge layers you also merge any masks sometimes I spend a while creating a mask on several different layers but then would like to merge that mask into one cannot find a way of doing this at present it would be so simple if merge layers merged masks
Also, in general, you can't merge the layer contents and masks separately - because you would not get the same result. (only works if they mask independent regions, if the masks overlap or the blend modes differ, you get a problem)
If you merge visible in your layers why can you not at the very same time merge visible with the masks attached to those layers why do they just disappear. Surely it is so much harder to blend layers together than masks. After all masks are just black and white?