I would like a feature that creates supports for a certain percentage or height range. For an example, if I have a part in which half is flat on the platform and the other half is raised 5 mm. Then there is an overhang on top. I would like to somehow have automatic supports for 0-5mm but nothing on top. I know I can manually remove supports, but this is impossible at times. Lets say I have a cylinder laying on its side. I would like external supports for the overhang but nothing internal. So an internal/external support may work too.
It sounds like you're having trouble clicking the internal regions of your part. One thing that might help is the cross-sectional view tool on the right-hand side of the program.
Version 3.0 now has a new option to only add support structures if they are touching the build platform. This can be used to avoid support structures inside your part.