Too early to tell for certain, but Safari Technology Preview 83 *might* have finally fixed that pesky Masto bug, wherein closing an image you've viewed at full size may reset one or more of the TL columns to the top. I'll be quite pleased if so - Firefox works fine most of the time, but tends to get bogged down sometimes, especially if any TL isn't left at the top, and a few hours' toots accumulate.