I chose columns under the gear icon, then dragged and dropped to get them into the desired order, but after reading a message and coming back to the inbox, the columns disappeared. They don't just revert to the previous order, they actually go away (except for subject) and have to be re-added. This only happens after reordering columns; if I leave the columns in the default order after adding them, they stay.
Is there a save button or something that I'm overlooking after drag and drop ordering of columns? Thanks!