The dialog box for adding a page or folder to the bookmarks bar extends beyond the monitor borders.

Steps to reproduce the issue:
1.Create multiple folders with several nesting levels (I have three).
2.Open the dialog box for adding a new folder or page to a third-level folder.
3.Then, you can try opening several more tree levels in this dialog box without collapsing them.
4.Click "Save" or "Enter."
5. After this, subsequent Add dialogs will always display the tree structure as it was when you last saved it. However, the dialog window extends beyond the screen, so much so that even collapsing all the branches doesn't help. You can only click Escape to close it.

Picture-in-Picture Improvements

To improve the PiP the horrible full area dimming effect on hover should be removed. Along with the inadequate volume adjustment (volume increasing) top > bottom (adequate adjustment is bottom > top or left > right).

*Btw, why on your screenshots and in demo the fake PiP is shown ?
The controls are visible (in different place though) what means the cursor on the PiP so the the PiP on your screenshot should be dimmed.

the volume control is fake also in your demo