In a simple, all-defaults test album with Lucid, if I click the "Next" arrow at top right, and then just wait a few seconds, the control bar disappears. There is then no way to get it back - mouseover at the top isn't producing any effect. This doesn't happen if I click in the area to the right of the slide image - it happens only if I use the control bar arrows.
I made a few modifications, although I could not reproduce it on High Sierra. I suspect this is due to the fact Safari triggers a mousemove on page load even though the mouse wasn't moved, which might be too early for the skin code, and triggers some error. Now I added a 2 second delay for the mouse move listener. Hopefully this is enough.
Okay, I probably forgot about that the detection of mouse/touch driven interface can be done later than the page is initialized, so now the skin is checking the interface type every time it hides the controls. Previously it could have happened the mouse move event listener is not engaged because at the time the interface type hasn't been decided yet, but later the controls still got hidden. https://laza.jalbum.net/Testing%20Lucid%20control%20bar/