Disappearing Bookmarks Toolbar Items Topic is solved

[0N10NKN16H7]

EDIT: This is a really niche problem. I would delete the thread, but it wouldn't let me.
Any idea why this happens?

Windows 8.1 x64
Pale Moon 27.4.2 x64

Steps to reproduce:
1. Open Pale Moon.
2. Apply the user style below (requires Stylish).
3. Open a HTML file in Pale Moon (specifically, I used Open with > Pale Moon).
4. Drag the HTML file's tab to a new window.

Expected result:
The bookmarks toolbar will appear when opening a new tab (my new tab page is about:blank) and the bookmark toolbar items will appear.

Actual result:
The bookmarks toolbar items should now be missing for that window, but the toolbar will expand as normal when on an about: page. The existing window's bookmarks toolbar should function normally. Disabling the userstyle does not fix the new window's bookmark toolbar.
Right-clicking the bookmarks toolbar produces this:

EDIT: Seems to only happen under certain circumstances with Stylish and this userstyle:

Code: Select all

@namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul");

#main-window:not([stylish-url^="about:"]):not([stylish-url^="chrome:"]) #PersonalToolbar /* hides bookmarks toolbar when browsing web pages */
{
  display: none !important;
}