Models that are loaded in the View Groups dialog are being removed after closing and reopening design. For every Model that is loaded the View Groups dialog adds an entry to the list but it doesn't always save after closing and reopening the drawing. Why?
The Manage View Groups dialog box is used for adding temporary views of each Model loaded. In addition to the temporary views, the active Model will always be listed and additional views groups can be saved. If a view group is added by selecting 'Create View Group' the entry will be saved. The 'LAST' Model loaded prior to exiting the drawing and saving the settings, the entry will be saved. All other temporary view will be discarded after exiting the design.*Note: When creating new Models in a Design file the Option for Creating View Groups is available for controlling. With this option toggled ON every Model that is loaded a View Group entry will be created and "Saved" every time.