feat: Disable opening link on split view if the limit is reached, b=(no-bug), c=common, split-view

src/zen/common/ZenSessionStore.mjs

@@ -87,7 +87,7 @@
     }
 
     async #waitAndCleanup() {
-      await SessionStore.promiseInitialized;
+      await SessionStore.promiseAllWindowsRestored;
       await this.#resolveGlanceTabs();
       this.#cleanup();
     }

src/zen/split-view/ZenViewSplitter.mjs

@@ -1151,6 +1151,7 @@ class ZenViewSplitter extends ZenDOMOperatedFeature {
     this.tabBrowserPanel.removeAttribute('zen-split-view');
     this.currentView = -1;
     this.toggleWrapperDisplay(false);
+    this.maybeDisableOpeningTabOnSplitView();
   }
 
   /**
@@ -1308,6 +1309,7 @@ class ZenViewSplitter extends ZenDOMOperatedFeature {
         });
       }
     });
+    this.maybeDisableOpeningTabOnSplitView();
   }
 
   /**
@@ -1861,6 +1863,24 @@ class ZenViewSplitter extends ZenDOMOperatedFeature {
       this.onLocationChange(gBrowser.selectedTab.linkedBrowser);
     }
   }
+
+  maybeDisableOpeningTabOnSplitView() {
+    document
+      .getElementById('cmd_zenSplitViewLinkInNewTab')
+      .setAttribute('disabled', !this.canOpenLinkInSplitView());
+  }
+
+  canOpenLinkInSplitView() {
+    const currentView = this.currentView;
+    if (currentView < 0) {
+      return true;
+    }
+    const group = this._data[currentView];
+    if (!group || group.tabs.length >= this.MAX_TABS) {
+      return false;
+    }
+    return true;
+  }
 }
 
 window.gZenViewSplitter = new ZenViewSplitter();