I had a File I/O form stub, that would open without showing the source or the form. If you clicked View>Source Editor, it would bring up an empty panel (no source). Also “View>Toggle Form/Unit View”, was greyed out. But if you ran it, apparently without a source file or a form, it would run as expected…showing the form. So it knew it was there.
If I clicked on the .lfm file, while Lazarus was open in this project, the source would pop up within Lazarus, but the view would still not be there. If I now clicked on a form control (such as label) the form would pop up.
At this point all the panels I expected were displaying. Except some controls were not displaying when you ran it. So I stretched out the form till everything displayed. And saved All. Now when I open the project everything is as I expect.