On wikitext editor, the help text that's at the end of the textarea and next to the toggle button is above the toggle buttont, and both can clash, making the button unclickable.

This happens specially on stretched messages or board descriptions, if browser window is resized so the text fills more than one line.

Since the text is above the button, clicking on it doesn't click the button, but the text. Also, text that clashes with the button may be difficult to read because of the button's background color.