Bug 1849221 - Create XULSTORE setting for Quick Filter keep filters applied. r=freaktechnik

- Create XULSTORE setting that can be persisted

Differential Revision: https://phabricator.services.mozilla.com/D186494

--HG--
extra : moz-landing-system : lando

mail/base/content/quickFilterBar.js

@@ -108,6 +108,16 @@ var quickFilterBar = {
         this.triggerQFTRovingTab(event);
       });
     }
+
+    document.getElementById("qfb-sticky").addEventListener("click", event => {
+      let stickyValue = event.target.pressed ? "true" : "false";
+      Services.xulStore.setValue(
+        XULSTORE_URL,
+        "quickFilterBarSticky",
+        "enabled",
+        stickyValue
+      );
+    });
   },
 
   /**