Certain buttons are not recognized in the YouTube UI

[eedo31]

I use styleboot mainly to make my UIs cleaner, especially after having already learned shortcuts for certain websites.
On YouTube for example, I removed most of the player buttons but apparently only some are removed while others are not, in particular I can't remove the "picture in picture" button (button.ytp-pip-button). The code is the same as the other keys but that one remains visible no matter what I do.
Can anyone help me? Maybe I'm doing something wrong?

Chrome 120.0.6099.225
Win11 23H2 22635.2915