Thank you @TroutMan. This is the first time I’ve ever learned that the preview pane could be closed, and how to do it.
Let’s see. https://www.youtube.com/watch?v=bhlZdP1uKyc
Inserting the link on the line doesn’t work.
However, it seems that inserting the link on its own line does work, except that you can’t go back to edit the post.
Thanks, everyone!
As noted above, this is because once the exact URL text has been used in a preview, then you can’t post that URL again. However, you can tweak the URL slightly by appending &1 or various other tweaks. Keep incrementing the number until it works (but remember that you must hide the preview window or be very quick about it). Increment again every time you make an edit.
I use &t=0, adding more zeroes as needed. Unless a specific point in the video is needed.
You can add an & and then almost anything afterward. But for this sort of thing, it tends to be easier to give specific instructions on what to do, rather than general instructions with all of the exceptions spelled out. &1, &2, etc. is easy to explain and understand, and hard to screw up.