fixTitlebarTooltips.uc.js

// ==UserScript==
// @name           Fix Titlebar Button Tooltips
// @version        1.0
// @author         aminomancer
// @homepage       https://github.com/aminomancer/uc.css.js
// @description    Since bug 1718629 (https://bugzilla.mozilla.org/show_bug.cgi?id=1718629), Firefox has tried to make the titlebar buttons (window controls) function more like native controls. In doing so, it allows the OS to draw tooltips for these buttons. So it prevents itself from showing redundant tooltips. That means we can't style the titlebar buttons' tooltips, they don't obey preferences, they disappear after 5 seconds on Windows, and they don't appear at all in fullscreen mode. Personally I would not be a fan of this change even if I didn't heavily customize Firefox's tooltips, because no matter what, OS tooltips are not going to be consistent with Firefox's tooltips, for reasons I mentioned. But in any case, we can fix this issue with JavaScript. It's caused by the titlebar-btn attribute. But removing that programmatically won't work because it's parsed by a C++ component when the buttons are connected. It's already too late by the time the script is running. So we need to recreate the DOM nodes without this attribute.
// @license        This Source Code Form is subject to the terms of the Creative Commons Attribution-NonCommercial-ShareAlike International License, v. 4.0. If a copy of the CC BY-NC-SA 4.0 was not distributed with this file, You can obtain one at http://creativecommons.org/licenses/by-nc-sa/4.0/ or send a letter to Creative Commons, PO Box 1866, Mountain View, CA 94042, USA.
// @include        *
// ==/UserScript==

class FixTitlebarTooltips {
    constructor() {
        this.markup = `<hbox class="titlebar-buttonbox-container" skipintoolbarset="true">
            <hbox class="titlebar-buttonbox titlebar-color">
                <toolbarbutton class="titlebar-button titlebar-min"
                            oncommand="window.minimize();"
                            data-l10n-id="browser-window-minimize-button"
                            />
                <toolbarbutton class="titlebar-button titlebar-max"
                            oncommand="window.maximize();"
                            data-l10n-id="browser-window-maximize-button"
                            />
                <toolbarbutton class="titlebar-button titlebar-restore"
                            oncommand="window.fullScreen ? BrowserFullScreen() : window.restore();"
                            data-l10n-id="browser-window-restore-down-button"
                            />
                <toolbarbutton class="titlebar-button titlebar-close"
                            command="cmd_closeWindow"
                            data-l10n-id="browser-window-close-button"
                            />
            </hbox>
        </hbox>`;
        let boxes = document.querySelectorAll(".titlebar-buttonbox-container");
        boxes.forEach((box) => box.replaceWith(MozXULElement.parseXULToFragment(this.markup)));
    }
}
new FixTitlebarTooltips();