diff --git a/webapp/components/channel_header.jsx b/webapp/components/channel_header.jsx
index 922f8b21c6..91060f5833 100644
--- a/webapp/components/channel_header.jsx
+++ b/webapp/components/channel_header.jsx
@@ -144,6 +144,7 @@ export default class ChannelHeader extends React.Component {
     }
     openRecentMentions(e) {
         if ((e.ctrlKey || e.metaKey) && e.shiftKey && e.keyCode === Constants.KeyCodes.M) {
+            e.preventDefault();
             this.searchMentions(e);
         }
     }
diff --git a/webapp/components/navbar_dropdown.jsx b/webapp/components/navbar_dropdown.jsx
index 162841f326..68ea625f86 100644
--- a/webapp/components/navbar_dropdown.jsx
+++ b/webapp/components/navbar_dropdown.jsx
@@ -71,6 +71,7 @@ export default class NavbarDropdown extends React.Component {
     }
     openAccountSettings(e) {
         if ((e.ctrlKey || e.metaKey) && e.shiftKey && e.keyCode === Constants.KeyCodes.A) {
+            e.preventDefault();
             this.setState({showUserSettingsModal: true});
         }
     }