For certain reasons I've recently been using Gmail via the web rather than using a mail program on my computer.
One of my habits is to clean up my inbox from time to time by searching for related emails and moving them into the appropriate folder. (Yes, I know there's a school of thought that this type of filing system is less effective than simply searching whenever you need to find something, but it works for me.)
So I might search the inbox for messages from a particular person (in Gmail, the search terms would be something like in:inbox from:email@example.com), select all, then manually deselect any that should remain in the inbox for now.
Then I'd move them to the appropriate folder, but in this situation Gmail replaces the "move to folder" button with a "move to inbox" button – even though they're already in the inbox!
I felt there must be a reasonably easy way to do this task, and a Google search revealed a YouTube video that explains what that is:
In a nutshell, you select the messages, add the label for the folder you want to move them to, and then archive them to remove the inbox label.
So thumbs up to Mike from Viziblee for the tip.