Fix unnecessary re-rendering of various components when typing in web UI (#15286)

app/javascript/mastodon/features/ui/components/columns_area.js

@@ -99,8 +99,13 @@ class ColumnsArea extends ImmutablePureComponent {
     if (this.props.singleColumn !== prevProps.singleColumn && !this.props.singleColumn) {
       this.node.addEventListener('wheel', this.handleWheel, supportsPassiveEvents ? { passive: true } : false);
     }
-    this.lastIndex = getIndex(this.context.router.history.location.pathname);
-    this.setState({ shouldAnimate: true });
+
+    const newIndex = getIndex(this.context.router.history.location.pathname);
+
+    if (this.lastIndex !== newIndex) {
+      this.lastIndex = newIndex;
+      this.setState({ shouldAnimate: true });
+    }
   }
 
   componentWillUnmount () {