Fix multiple pinned post issues (#6887)

webapp/components/sidebar_right/sidebar_right.jsx

@@ -77,12 +77,12 @@ export default class SidebarRight extends React.Component {
     }
 
     shouldComponentUpdate(nextProps, nextState) {
-        return !Utils.areObjectsEqual(nextState, this.state) || !Utils.areObjectsEqual(nextProps, this.props);
+        return !Utils.areObjectsEqual(nextState, this.state) || this.props.postRightVisible !== nextProps.postRightVisible;
     }
 
     componentWillUpdate(nextProps, nextState) {
         const isOpen = this.state.searchVisible || this.props.postRightVisible;
-        const willOpen = nextState.searchVisible || nextState.postRightVisible;
+        const willOpen = nextState.searchVisible || nextProps.postRightVisible;
 
         if (!isOpen && willOpen) {
             trackEvent('ui', 'ui_rhs_opened');