When editing the annotations of a rendered viewport, you may notice that after using the edit annotations command, the viewport reverts back to wireframe:
Before editing annotations:
After editing annotations:
This can be prevented under File > Document Settings > Document Preferences > Display, by checking the "Save Viewport Cache" option. This option saves the rendered result of a viewport even when editing annotations or after closing and re-opening a file, at the cost of additional disk space.
Edited by JimW