its bugged then, i only have one mask layer and its clearing instead of painting black. Mask was created as reveal all, tried with hide all and ""works"" (it stills clears instead of painting white, since its hide all i assume clear will fill white instead of white (?))
I think its also my fault, i thought since you let us choose "show all" and "hide all", the layer "remembered" which type of mask it is, so "clear" reacted to that, but i guess picking "show" or "hide" is just a filling shortcut so "clear" can only do one thing in the end, in this case deleting the color information of the mask layer (turning the selection transparent) :\