Firefox Native Controls

Simple source code patches that re-enable and reimplement native controls for modern versions of Firefox. Requires modifying Firefox installation files, but you don't need to use a custom build of Firefox altogether.

It is still recommended that you use ESR and disable automatic updates. Unfortunately, updating is just a sacrifice you have to make to theming. However, I may write a custom updater with this mod in consideration, eventually. All prebuilt releases are distributed for ESR releases of Firefox.

The only potential caveat: Widevine support. I don't know if this is controlled by xul.dll or not, but there is a file beside it called xul.dll.sig in official Firefox builds that has information regarding a Widevine certificate (and is otherwise seemingly completely unused). If you are based, this will not matter to you.

At the moment, it is required that you still manually disable non-native controls in order to use this.

I installed this because of a theme, and I get an error!

Here are some simple troubleshooting guidelines which fix 99% of reported problems:

If the error mentions "XULRunner" and something about a platform version mismatch, then you need to download a version of this patch corresponding to your specific Firefox version.

If the error says something about XPCOM failing to initialise, then it's most likely that you have a platform architecture mismatch. That means you're using a 32-bit version of Firefox. Mozilla just gives random 64-bit Windows users a 32-bit version for some reason, or at least I don't see any pattern. You can verify this quickly by seeing if Firefox is in "Program Files (x86)" instead of "Program Files". If you have a 32-bit version, then you just need to install the 64-bit version, which you can find on https://ftp.mozilla.org/pub/firefox/releases/

Change documentation

Scrollbars
Other controls (statusbar, resizer, tooltips): Much of the same applies here as it does to scrollbars. Old code was lifted from previous versions of Firefox, typically the commit just before removal, and for the most part just copy/pasted back in directly.

Installing prebuilt versions

In the releases section on the right, there are pre-compiled versions of xul.dll for Firefox ESR.

Check your Firefox version and download the right version for the version that you have, and then replace xul.dll in the installation path with the file that you downloaded.

If you don't trust the versions I built myself, then you can mix the provided patches with the Firefox source code (see the following section). The prebuilt versions are just provided for convenience, because the Firefox source code is pretty big and takes a while to compile.

Step-by-step:

Download the release on the right side of the page. If your version is unsupported, then you will have to build the changes from source.
Replace C:\Program Files\Mozilla Firefox\xul.dll with the downloaded xul.dll file.
Restart Firefox.

Note: Unfortunately, it's not possible to create one distribution that works across patches. This is because the XUL version check is baked into firefox.exe rather than xul.dll.

Building from source

Clone Firefox for yourself, and then mix in the patches as needed. Note that when you clone, it will put in the mozilla-central branch. You probably don't want this as these correspond to the latest Nightly builds, which will mean that the produced xul.dll binary will likely be incompatible with the current build environment.

After cloning, navigate to .hg/hgrc in the source directory and change the default path to the branch of your preferred build. For example, I changed it to https://hg.mozilla.org/releases/mozilla-esr115 in order to access specific tags for the ESR 115 release. You can usually then find specific tags relating to subversions here: https://hg.mozilla.org/releases/mozilla-esr115/tags ("tags" tab in the Mercurial web viewer).

Since Firefox uses Mercurial for version control, it may be a little unfamiliar to you. You "update", rather than "checkout", different branches. So after you make those changes, I think you just do something like hg pull -u -r FIREFOX_115_3_1esr_RELEASE to switch to the specific branch. pull makes it get the specific version from remote, and -u means to update.

Run ./mach build to build Firefox from source and then ./mach run to test it. Here is a Windhawk mod that I use to quickly test classic theme for Firefox only (where I make a copy of firefox.exe named firefoxa.exe):

// ==WindhawkMod==
// @id              firefoxa-classic-theme-test
// @name            [Testing] firefox classic theme
// @description     The best mod ever that does great things
// @version         0.1
// @author          ephemeralViolette
// @include         firefoxa.exe
// @compilerOptions -luxtheme
// ==/WindhawkMod==

#include <uxtheme.h>

BOOL Wh_ModInit()
{
    SetThemeAppProperties(0);
    return TRUE;
}

Also, currently there is a bug you need to be aware of. After disabling widget.non-native-theme.enabled, you must restart Firefox completely, or else the scrollbars will simply not render. I do not know why this happens exactly (maybe the native theme isn't loaded upon disabling the property? I haven't looked at other controls).

After building, the xul.dll file can be found in somewhere like obj-x86_64-pc-windows-msvc/dist/bin in the source code root, which looks just like C:\Program Files\Mozilla Firefox.

Distribution method

Also because Firefox uses Mercurial rather than Git, I found it would be more trouble than it's worth to attempt to post a modified codebase onto GitHub. I initially thought to fork mozilla/gecko-dev, but the commit identifiers for this repository do not at all align with their Mercurial revision identifiers, so it is less than worthless. Also, I found I couldn't even find certain tags which were useful to access in the Mercurial version.