diff --git a/src/components/structures/UserMenuButton.tsx b/src/components/structures/UserMenuButton.tsx
index d8f96d4a91..5fbab796a6 100644
--- a/src/components/structures/UserMenuButton.tsx
+++ b/src/components/structures/UserMenuButton.tsx
@@ -80,7 +80,7 @@ export default class UserMenuButton extends React.Component<IProps, IState> {
     private isUserOnDarkTheme(): boolean {
         const theme = SettingsStore.getValue("theme");
         if (theme.startsWith("custom-")) {
-            return getCustomTheme(theme.substring(0, 7)).is_dark;
+            return getCustomTheme(theme.substring("custom-".length)).is_dark;
         }
         return theme === "dark";
     }
diff --git a/src/stores/room-list/RoomListStoreTempProxy.ts b/src/stores/room-list/RoomListStoreTempProxy.ts
index 0268cf0a46..0a173d53a9 100644
--- a/src/stores/room-list/RoomListStoreTempProxy.ts
+++ b/src/stores/room-list/RoomListStoreTempProxy.ts
@@ -31,11 +31,14 @@ export class RoomListStoreTempProxy {
         return SettingsStore.isFeatureEnabled("feature_new_room_list");
     }
 
-    public static addListener(handler: () => void) {
+    public static addListener(handler: () => void): RoomListStoreTempToken {
         if (RoomListStoreTempProxy.isUsingNewStore()) {
-            return RoomListStore.instance.on(UPDATE_EVENT, handler);
+            const offFn = () => RoomListStore.instance.off(UPDATE_EVENT, handler);
+            RoomListStore.instance.on(UPDATE_EVENT, handler);
+            return new RoomListStoreTempToken(offFn);
         } else {
-            return OldRoomListStore.addListener(handler);
+            const token = OldRoomListStore.addListener(handler);
+            return new RoomListStoreTempToken(() => token.remove());
         }
     }
 
@@ -47,3 +50,12 @@ export class RoomListStoreTempProxy {
         }
     }
 }
+
+export class RoomListStoreTempToken {
+    constructor(private offFn: () => void) {
+    }
+
+    public remove(): void {
+        this.offFn();
+    }
+}
diff --git a/src/stores/room-list/TagWatcher.ts b/src/stores/room-list/TagWatcher.ts
index 1fb5223e00..22302b695d 100644
--- a/src/stores/room-list/TagWatcher.ts
+++ b/src/stores/room-list/TagWatcher.ts
@@ -74,6 +74,11 @@ export class TagWatcher {
                 this.store.removeFilter(filter);
             }
 
+            // Destroy any and all old filter conditions to prevent resource leaks
+            for (const filter of this.filters.values()) {
+                filter.destroy();
+            }
+
             this.filters = newFilters;
         }
     };