Update watermark preference based on build type and enhance URL bar positioning

src/browser/base/content/ZenUIManager.mjs

@@ -131,9 +131,10 @@ var gZenVerticalTabsManager = {
     this._toolbarOriginalParent = document.getElementById('nav-bar').parentElement;
 
     gZenCompactModeManager.addEventListener(updateEvent);
-    this._updateEvent();
     this.initRightSideOrderContextMenu();
 
+    window.addEventListener('DOMContentLoaded', updateEvent, { once: true });
+
     const tabs = document.getElementById('tabbrowser-tabs');
 
     XPCOMUtils.defineLazyPreferenceGetter(this, 'canOpenTabOnMiddleClick', 'zen.tabs.newtab-on-middle-click', true);

src/browser/base/content/zen-styles/zen-urlbar.css

@@ -20,6 +20,9 @@
   min-width: 45%;
   --urlbar-container-height: 55px !important;
   --urlbar-margin-inline: 10px !important;
+  position: fixed;
+
+  top: calc(var(--zen-toolbar-height) * 4);
   left: 50%;
   transform: translateX(-50%);