1. This is a global style and I recommend turning it on only when you need it.

2. This style will only work if the site is using CSS to block your ability to select text / highlight. If it doesn't work the site is likely using Javascript or some other method to stop you. (In that case, find a browser extension / add on / setting to easily block Javascript.)

3. Also, really useful when the website chooses obnoxious colors for highlighting text. My style changes the highlighter to white text on a black background so you can read it easily.