feat: Dont close essentials when they are unloaded, b=no-bug, c=folders, tabs

src/zen/folders/ZenFolders.mjs

@@ -1054,7 +1054,7 @@
           // We don't need to do anything if the URL is invalid. e.g. about:blank
         }
         let tabLabel = tab.label || '';
-        let iconURL = gBrowser.getIcon(tab) || PlacesUtils.favicons.defaultFavicon;
+        let iconURL = gBrowser.getIcon(tab) || PlacesUtils.favicons.defaultFavicon.spec;
 
         icon.src = iconURL;
 

src/zen/folders/zen-folders.css

@@ -393,6 +393,8 @@ zen-folder {
   border: none !important;
   outline: none !important;
   flex: 1;
+  text-overflow: ellipsis;
+  white-space: nowrap;
 }
 
 #zen-folder-tabs-list {
@@ -416,6 +418,8 @@ zen-folder {
   flex-shrink: 0;
   margin-inline-end: 10px;
   margin-inline-start: 4px;
+  fill: currentColor;
+  -moz-context-properties: fill;
 }
 
 .folders-tabs-list-item-labels {

src/zen/tabs/ZenPinnedTabManager.mjs

@@ -812,7 +812,9 @@
             if (selectedTab.group?.hasAttribute('split-view-group')) {
               tabsToUnload = selectedTab.group.tabs;
             }
-            const allAreUnloaded = tabsToUnload.every((tab) => tab.hasAttribute('pending'));
+            const allAreUnloaded = tabsToUnload.every(
+              (tab) => tab.hasAttribute('pending') && !tab.hasAttribute('zen-essential')
+            );
             if (allAreUnloaded && closeIfPending) {
               return await this._onCloseTabShortcut(event, selectedTab, { behavior: 'close' });
             }
@@ -897,7 +899,7 @@
         const faviconData = await PlacesUtils.favicons.getFaviconForPage(pageUrl);
         if (!faviconData) {
           // empty favicon
-          return 'data:image/png;base64,';
+          return null;
         }
         return faviconData.dataURI;
       } catch (ex) {
@@ -1205,7 +1207,7 @@
       } else {
         tab.setAttribute('zen-pinned-changed', 'true');
       }
-      tab.style.setProperty('--zen-original-tab-icon', `url(${pin.iconUrl.spec})`);
+      tab.style.setProperty('--zen-original-tab-icon', `url(${pin.iconUrl?.spec})`);
     }
 
     removeTabContainersDragoverClass(hideIndicator = true) {