Fix issues with the new topic dialog (#8608)

src/hooks/useFocus.ts

@@ -0,0 +1,29 @@
+/*
+Copyright 2022 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import { useState } from "react";
+
+export default function useFocus(
+): [boolean, {onFocus: () => void, onBlur: () => void}] {
+    const [focused, setFocused] = useState(false);
+
+    const props = {
+        onFocus: () => setFocused(true),
+        onBlur: () => setFocused(false),
+    };
+
+    return [focused, props];
+}