1406476 - userChrome.css doesn't apply to about:config or Library in a tab

Status: RESOLVED INVALID

(Core :: XUL, defect)

Description

[Gingerbread Man]

Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:56.0) Gecko/20100101 Firefox/56.0
20170926190823
Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:58.0) Gecko/20100101 Firefox/58.0
20171006100327

Steps to reproduce:
1. Create a brand new profile.
2. Before starting Firefox, inside that profile folder, create a subfolder named chrome. In there, create a new text file named userChrome.css, paste the following in it, then save and close the file.

@namespace url(http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul);
@-moz-document url(chrome://browser/content/places/places.xul), url(about:config) {
* { font: 28px Georgia !important; }
}

3. Start Firefox in the new profile created earlier.
4. Open two new tabs, then open these URLs in them. Click the "I accept the risk!" button for the second one.
chrome://browser/content/places/places.xul
about:config

Actual results:
The font style and size is unchanged from the default.

Expected results:
The font should be Georgia at 28px.

Notes:
userChrome.css does apply the style to a regular Library window (Ctrl+Shift+B). Stylish 2.0.7 has no trouble applying this style in either of the aforementioned tabs.

Comment 1

[Gingerbread Man]

The elements are in the XUL namespace, but the code actually needs to go in userContent.css:

@namespace url(http://www.w3.org/1999/xhtml);
@namespace xul url(http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul);

@-moz-document url(chrome://browser/content/places/places.xul), url(about:config) {
xul|* { font: 28px Georgia !important; }
}