Unable to select Copper Fill objects on the currently selected layer when there are Copper Fill arias in the same location on multiple layers, it randomly selects the object on the bottom layer regardless of current layer selection. I think it has something to do with a difference the clickable widths of selecting the line in some code somewhere between "selection from current layer" over "selection from all layers". if your very careful as to clicking exactly on the Copper fill bounding line you can select the fill on the active layer, i assume it is only reacting to 1 pixel wide, where the coper fill arias are reacting to a click aria wider than a single pixel wide making the inactive layers accidentally easer to select. quite annoying, the "Add/Remove Vias" option in copper fill does not follow grid snap rules making it impossible to add extra vias manually that line up with vias already placed on the board unless you manually pace all vias