diff --git a/src/matrix/room/timeline/Timeline.js b/src/matrix/room/timeline/Timeline.js
index eab71255..ecba1f2a 100644
--- a/src/matrix/room/timeline/Timeline.js
+++ b/src/matrix/room/timeline/Timeline.js
@@ -32,7 +32,8 @@ export class Timeline {
         this._disposables = new Disposables();
         this._pendingEvents = pendingEvents;
         this._clock = clock;
-        this._remoteEntries = null;
+        // constructing this early avoid some problem while sync and openTimeline race
+        this._remoteEntries = new SortedArray((a, b) => a.compare(b));
         this._ownMember = null;
         this._timelineReader = new TimelineReader({
             roomId: this._roomId,
@@ -96,7 +97,6 @@ export class Timeline {
     }
 
     _setupEntries(timelineEntries) {
-        this._remoteEntries = new SortedArray((a, b) => a.compare(b));
         this._remoteEntries.setManySorted(timelineEntries);
         if (this._pendingEvents) {
             this._localEntries = new MappedList(this._pendingEvents, pe => {
@@ -159,7 +159,9 @@ export class Timeline {
         // Once the subscription is setup, MappedList will set up the local
         // relations as needed with _applyAndEmitLocalRelationChange,
         // so we're not missing anything by bailing out.
-        if (!this._localEntries.hasSubscriptions) {
+        //
+        // _localEntries can also not yet exist
+        if (!this._localEntries?.hasSubscriptions) {
             return;
         }
         // find any local relations to this new remote event
@@ -301,4 +303,4 @@ export function tests() {
             assert.equal(Array.from(timeline.entries)[0].isRedacting, true);
         }
     }
-}
\ No newline at end of file
+}
diff --git a/src/platform/web/ui/common.js b/src/platform/web/ui/common.js
index 9fbafcdf..15a522c7 100644
--- a/src/platform/web/ui/common.js
+++ b/src/platform/web/ui/common.js
@@ -14,10 +14,13 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-const container = document.querySelector(".hydrogen");
+let container;
 
 export function spinner(t, extraClasses = undefined) {
-    if (container.classList.contains("legacy")) {
+    if (container === undefined) {
+        container = document.querySelector(".hydrogen");
+    }
+    if (container?.classList.contains("legacy")) {
         return t.div({className: "spinner"}, [
             t.div(),
             t.div(),