Form is destroyed and freezes Pan X

I had just finished setting up a single record data entry form to tab back to front and started testing it when all the form objects disappeared as if I had selected all then pressed Delete. I didn’t do that or anything remotely like that. The Close Box didn’t work and Pan X wouldn’t quit from the Menu so I had to force quit. Reopening the file showed that Pan X had saved the file. I opened the file’s View as List form which has the exact same objects, selected all, deselected the Header and Data Tile, Copied, then went to the single record form and pressed Command V to Paste in the form objects. Pan X froze and I had to force quit. This is weeks of time that looks like a waste as I was too trusting to make file backups.