Fix FilePanel and NotificationPanel overscroll issues

src/components/structures/FilePanel.js

@@ -230,6 +230,7 @@ class FilePanel extends React.Component {
                     className="mx_FilePanel"
                     onClose={this.props.onClose}
                     previousPhase={RightPanelPhases.RoomSummary}
+                    withoutScrollContainer
                 >
                     <TimelinePanel
                         manageReadReceipts={false}

src/components/structures/NotificationPanel.js

@@ -60,7 +60,7 @@ class NotificationPanel extends React.Component {
             content = <Loader />;
         }
 
-        return <BaseCard className="mx_NotificationPanel" onClose={this.props.onClose}>
+        return <BaseCard className="mx_NotificationPanel" onClose={this.props.onClose} withoutScrollContainer>
             { content }
         </BaseCard>;
     }

src/components/structures/TimelinePanel.js

@@ -104,8 +104,8 @@ class TimelinePanel extends React.Component {
         // shape property to be passed to EventTiles
         tileShape: PropTypes.string,
 
-        // placeholder text to use if the timeline is empty
-        empty: PropTypes.string,
+        // placeholder to use if the timeline is empty
+        empty: PropTypes.node,
 
         // whether to show reactions for an event
         showReactions: PropTypes.bool,