Feature Request: Invert the logic: Add "Enable area"

[erffrfez]

I have used this add-on quite often, and THANKS. There have been times when I've wanted to exclude all but (eg) 3 parts on a bed (the ones that failed with the initial print). Perhaps one part broke, or didn't stick so need to print that again, but also need to deal with the 2 other parts that then got a whole bunch of added 'spaghetti'. This can be quite a lengthy process to do in the plugin, adding multiple exclude areas. I'd like to be able to mark a big area in red (exclude it as can do now), then mark just the parts to be printed in green (re-enable them for printing.) Instead of doing this:

we'd do four circles, one to turn things off, then individually turn them on again:

For consideration please. :)

[semicolonmystery]

I totally agree it would be great if something like this would be implemented.