The atom I had selected in the trial puzzle for compound bonus=ses in devprev persisted in empty space when switching to the other small molucule puzzle. While loading, the splash screen 'loading' was overwritten partially by the small molecule selection popup window. It cannot be removed with the 'clear atom selection' icon.
BUG
I'm seeing something similar switching between the test puzzle https://fold.it/puzzles/2013493 and puzzle 2219 https://fold.it/puzzles/2013502
If the "Small-Molecule Design" panel is open, it shows up during "Refreshing shared solutions" while the next puzzle is loading. Any segment notes also peek through at this point.
If atoms are selected on the first puzzle, the selection halos are still shown on the next puzzle. The "Clear atom selection" button has no effect. Switching back to the first puzzle, the selection halos are still there, but still can't be cleared.
The halos are not shown if you switch to non-SMD puzzle, such as the revisiting puzzle or the cAMP ligand binder puzzle. But they're still there is you switch to one of the SMD puzzles.
Restarting Foldit does clear the selection halos.
Thank you very much for reporting this! We were able to repeat the issue, and are working on resolving the persistence of the atom selection and appearance of the "Small-Molecule Design" panel when switching puzzles.