When using the insert link button; its does not handle special characters unless they have already been escaped. Could the insert link function check the inputted text; and then run it through the URL escape character table replacing invalid characters before inserting into the body of the text. Here is a table of characters to find and replace in the link string https://www.werockyourweb.com/url-escape-characters/ Yes links should already been escaped before you paste them in; however there are some applications (cough cough Microsoft Word) that when you copy and paste links from them in from you still have spaces that are not converted to %20 and relies on the browser to do the interpretation etc. Extra points of course for being able to pasting rich text with links and have it converted to markdown on the fly.