diff --git a/src/components/views/voip/CallView.tsx b/src/components/views/voip/CallView.tsx
index a7ad6ef8c6..b49e729244 100644
--- a/src/components/views/voip/CallView.tsx
+++ b/src/components/views/voip/CallView.tsx
@@ -505,6 +505,9 @@ export default class CallView extends React.Component<IProps, IState> {
         /> : null;
 
         let screensharingButton;
+        // Screensharing is possible, if we can send a second stream and identify
+        // it using SDPStreamMetadata or if we can replace the already existing
+        // usermedia track by a screensharing track
         if (this.props.call.opponentSupportsSDPStreamMetadata() || this.props.call.type === CallType.Video) {
             screensharingButton = (
                 <AccessibleButton