Hmm, how did that work? If I drag from either the padlock in the address bar or an item on the Bookmarks menu, the right-click jump list does not show when I hover the taskbar icon. Did it show before, or where did you drop the link?

Oh... I remember a workaround: you can drag the bookmark to the desktop first to create a Windows Favorite, edit the name if needed, and then drag and drop that on the Firefox icon (this creates a clear prompt about pinning it). Does that method still work for you?

That does work, but I never had to do that before. One more thing to add to this. There are some Pinned URL's that do not go to their respective websites when clicked on while firefox is closed. They launch the browser, but bring me to a blank tab. Once firefox is open, clicking on the pinned URL does bring me to the site. Kind of defeats the purpose of pinning a site.

I guess I should also answer your question. First, I would click and drag a bookmark from the bookmarks menu and drop it on the firefox icon. That would pin that bookmark url to the icon. It would give me an "arrow" indicator showing I could pin it. Now it gives me a circle with a slash and does not allow me to pin. The only way I know of to reveal the pinned sites is to right click the taskbar icon for firefox.

This seems to have occurred since the most recent Firefox upgrade.

Hopefully someone else uses this feature more than me and is attuned to what's going on.

Does it make a difference if you hold down the Ctrl key while dragging the bookmark?

I tried that following your post and it does not resolve the issue.