Create a highlighting palette for temporary use, with a bunch of styles in it.
Apply some of those styles to some places in your resources.
Delete the highlighting palette.
All the places that were highlighted with it get converted to light yellow highlighting. I'm not sure this is what I'd want to have happen if I intentionally deleted a palette. I have just suggested to another user that he could use palettes for temporary use like this and then delete them when he was done with them. There's no way to find all the highlighting marks that were left behind if you did a bunch of highlighting for a temporary purpose and then wanted to get rid of it all at once. I thought deleting a temporary palette would be the easiest way to do it, but due to the way this behaves, that isn't reliable.
I'm sure this was done intentionally to avoid having to put up a warning message to the user: if you delete this palette you will lose all the highlighting that you've done with styles from this palette. Are you sure you want to do this? But I actually think that would be preferable to assuming that the user wants to keep those locations highlighted and just convert them all to some basic default.