I've accidentally created some desktop sticky notes on my taskbar:



Right clicking on one gives a context menu without an option to delete, and pressing Delete or Backspace with various modifiers doesn't do anything.

To remove panel widgets, -right click on a blank spot the taskbar somewhere, and select Edit Panel. You may have to unlock widgets first.
Or, click the configuration button on the far right of the panel (again, you may have to unlock widgets via the right click menu) .

Now, mousing over items will show the Remove option.

That did it, thanks.