Move `initActiveTab()` from change view into model The change view just reflects the `tab` property of the view state. Release-Notes: skip Change-Id: I0a5c139878caa0b9432401520b6296cb0d9fdfed

diff --git a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.ts b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.ts
index ac4d30f..2b594be 100644
--- a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.ts
+++ b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.ts

@@ -626,7 +626,7 @@
     subscribe(
       this,
       () => this.getViewModel().tab$,
-      t => (this.activeTab = t ?? Tab.FILES)
+      t => (this.activeTab = t)
     );
     subscribe(
       this,
@@ -826,8 +826,7 @@
             new Error('Mismatch of headers and content.')
           );
         }
-      })
-      .then(() => this.initActiveTab());
+      });
 
     this.throttledToggleChangeStar = throttleWrap<KeyboardEvent>(_ =>
       this.handleToggleChangeStar()
@@ -1631,9 +1630,8 @@
   override updated() {
     const tabs = [...queryAll<HTMLElement>(this.tabs!, 'paper-tab')];
     const tabIndex = tabs.findIndex(t => t.dataset['name'] === this.activeTab);
-    assert(tabIndex !== -1, `tab ${this.activeTab} not found`);
 
-    if (this.tabs!.selected !== tabIndex) {
+    if (tabIndex !== -1 && this.tabs!.selected !== tabIndex) {
       this.tabs!.selected = tabIndex;
     }
   }
@@ -2078,22 +2076,6 @@
 
     this.changeNum = this.viewState.changeNum;
     this.loadData(true);
-
-    this.getPluginLoader()
-      .awaitPluginsLoaded()
-      .then(() => {
-        this.initActiveTab();
-      });
-  }
-
-  private initActiveTab() {
-    let tab = Tab.FILES;
-    if (this.viewState?.tab) {
-      tab = this.viewState?.tab as Tab;
-    } else if (this.viewState?.commentId) {
-      tab = Tab.COMMENT_THREADS;
-    }
-    this.setActiveTab(new CustomEvent('show-tab', {detail: {tab}}));
   }
 
   // Private but used in tests.

diff --git a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_test.ts b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_test.ts
index 31cfa17..f946794 100644
--- a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_test.ts
+++ b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_test.ts

@@ -670,19 +670,6 @@
       assert.equal(element.activeTab, 'change-view-tab-header-url');
     });
 
-    test('param change should switch primary tab correctly', async () => {
-      assert.equal(element.activeTab, Tab.FILES);
-      // view is required
-      element.changeNum = undefined;
-      element.viewState = {
-        ...createChangeViewState(),
-        ...element.viewState,
-        tab: Tab.COMMENT_THREADS,
-      };
-      await element.updateComplete;
-      assert.equal(element.activeTab, Tab.COMMENT_THREADS);
-    });
-
     test('invalid param change should not switch primary tab', async () => {
       assert.equal(element.activeTab, Tab.FILES);
       // view is required

diff --git a/polygerrit-ui/app/models/views/change.ts b/polygerrit-ui/app/models/views/change.ts
index 4a14a80..3ac79d0 100644
--- a/polygerrit-ui/app/models/views/change.ts
+++ b/polygerrit-ui/app/models/views/change.ts

@@ -290,7 +290,11 @@
 
   public readonly childView$ = select(this.state$, state => state?.childView);
 
-  public readonly tab$ = select(this.state$, state => state?.tab);
+  public readonly tab$ = select(this.state$, state => {
+    if (state?.commentId) return Tab.COMMENT_THREADS;
+    if (state?.tab) return state.tab;
+    return Tab.FILES;
+  });
 
   public readonly checksPatchset$ = select(
     this.state$,