Toggle doesn't work when URLs contain special characters

[sonofevil]

Sometimes URLs have special characters like umlauts etc. Newer Firefox versions automatically convert the codes used to represent those characters in the HTML source (such as %C3%B8 for ø) back into the respective character when displaying URLs in the search bar or on link hover, but I don't know if that has anything to do with this bug.

Attempting to toggle links with such characters fails - they remain in their previous state. Could there perhaps be a mismatch between how these characters are represented in the search string the extension uses to search through the browser history and how those characters are represented in the browser history?