When typing underscores (such as for file names), the WYSIWYG editor automatically replaces them and italicizes the text within. This is very annoying behavior.
It's a particularly poor UX when you've already combated the editor successfully so your text has underscores in it, but if you then later on type another underscore. It will look back and match with a previous underscore that's far away. This disrupts large amounts of text in an unexpectedly non-local way.
Here's an example of how annoying it can be. Imagine I have entered the equivalent of this HTML:
<code>a_b_c_d</code> and some text. And sentences. Then a
When you type an underscore, you don't get an underscore, you get this:
<code>a_b_c<i>d</i></code><i> and some text. And sentences. Then a</i>
If you type another underscore, this happens:
<code>a_b<i>cd</i></code><i> and some text. And sentences. Then a</i>
There seems to be no way to work around this until all of the underscores is gone. Very annoying.
Solutions:
  • preferred: remove this functionality entirely. If you want italics, you can use the toolbar or the keyboard shortcut
  • or, at least disable this functionality within text that's formatted as "code"
  • or, if you don't disable it then at least prevent the lookback from spanning across multiple words, multiple sentences, or multiple format spans.