Occasionally I want to cut a series of hole out of a fill, e.g. where I've flooded tiling over a roof in elevation or plan, and then need to cut around the roof vents.
I've noticed that, when I select the fill, and then the 'minus' from the pet palette, sometimes, I can work my way around the fill cutting first one hole and then another. Other times (and this appears to be totally random!) after cutting one hole, I have to return to the edge of the fill and click the 'minus' on the pet palette after each hole before I can do the next. This is a pain, but I can't find any reason why it works one time and not the next.
Does anyone have any clues?