When I go to (Settings -> BuddyPress -> Components) and unchecked some of the components such as Notification and Activity Streams, I found the content of the sidebar will be reduced as well. But the problem is when I unchecked all the components, the content (my posts) is still there.
It’s not working. It seems like the content of the sidebar is not come from the appearance->widget. This is because when I leave it blank or delete all the content of widget. The sidebar is still show on the page. Nothing is changing.