It's called "Additive Selection". I've got mine set up like that because it's the closest CSP can get to an approximation of what PS can do. The problem is that additive selection still allows the user to make easy errors which then need to be undone or edited. Nothing is faster or more accurate than zipping around an object in polygonal mode. Being able to move instantly back and forth between that and freehand selection means you can select extremely complex shapes extremely fast. CSP requires the user to select little bits at a time or fill in the area with a painted mask. -Both of those systems work, but I find them clumsy and slow and prone to errors. It's like trying to cut out cloth with child's safety scissors rather than a grown up's tools.