In Vectorworks 2017 and newer, you may find that while you zoom or at different zoom levels some objects disappear.
If this occurs, please go to Vectorworks Peferences > Display > Navigation Graphics and adjust the setting to be either "Good Performance & Compatibility" or "Best Compatibility".
The occasional issue with some objects disappearing is related to the new VGM for Top/Plan view feature and is dependant on your computer's specifications and how your file is built.
Switching the setting described above should solve the issue for you. If it doesn't, please do get in touch with us.
For more information about the VGM for Top/Plan view feature, watch this video: