URL bar cannot be overlapped by any other element

[srjjgm]

In previous versions of Firefox, I used CSS code that placed find bar (findbar) and status panel (#statuspanel) on top of the address bar, in the right corner of the browser, with a semi-transparent background. This basically required "position: absolute (or fixed)" and positioning (top, bottom, right, etc.).

Now, when I do this, the website addresses, the bookmark icon (star) and other icons in the address bar remain fully visible and are not partially obscured by the semi-transparent background. So I had to change the code and place the findbar and statuspanel on top of the tab bar. It doesn't look bad, but I would have preferred to have them on top of the address bar.

Mozilla has "locked" the z-index of the URL bar so that it cannot be overlaid by any other element. I read somewhere, maybe on Reddit, that this is a bug, but some people also say it is for security reasons. Is it possible for a uc.js script or JS code inside the config.js file to "unlock" the z-index of the address bar, so that a CSS style can overlay another element on top of it?

[Sneakpeakcss]

This should stop #urlbar and #searchbar-new from staying in the top layer until they're opened.

// prevent-urlbar-toplayer.uc.js

(() => {
  function init() {
    for (const u of document.querySelectorAll("#urlbar, #searchbar-new")) {
      // prevent closed URL/search bars from staying in the top layer
      const update = () => u.view.isOpen ? u.showPopover() : u.hidePopover();
      new MutationObserver(update).observe(u, {
        attributes: true,
        attributeFilter: ["breakout", "breakout-extend"]
      });
      update();
    }
  }

  if (typeof gBrowserInit !== "undefined" && gBrowserInit.delayedStartupFinished) {
	init();
  } else {
	const delayedListener = (subject, topic) => {
	  if (topic === "browser-delayed-startup-finished" && subject === window) {
		Services.obs.removeObserver(delayedListener, topic);
		init();
	  }
	};
	Services.obs.addObserver(delayedListener, "browser-delayed-startup-finished");
  }
})();