--- a/devtools/client/webconsole/new-console-output/reducers/messages.js
+++ b/devtools/client/webconsole/new-console-output/reducers/messages.js
@@ -248,17 +248,18 @@ function messages(state = MessageState()
           });
       }
       return openState;
 
     case constants.MESSAGE_CLOSE:
       const closeState = {...state};
       let messageId = action.id;
       let index = closeState.messagesUiById.indexOf(messageId);
-      closeState.messagesUiById = [...closeState.messagesUiById].splice(index, 1);
+      closeState.messagesUiById.splice(index, 1);
+      closeState.messagesUiById = [...closeState.messagesUiById];
 
       // If the message is a group
       if (isGroupType(messagesById.get(messageId).type)) {
         // Hide all its children
         closeState.visibleMessages = visibleMessages.filter(id =>
           getParentGroups(messagesById.get(id).groupId, groupsById)
             .includes(messageId) === false
         );