Recently started to get an issue with Pro20. I get what I can only describe as a ghost section plane. It can not be highlighted, chosen,deleted etc. But when I orbit or zoom parts of my model disappear behind something. This happens even on a basic drawing. Any clues?
Sounds like clipping. Search the forum and the SketchUp help site for tons more information.
Many thanks quick read and I seem to have fixed it by clicking zoom extents.