Fix notification overlay making "added" notification disappear on touchables

When notification doesn't fit viewport on touch-enabled devices, it makes the canvas extend to its boundaries, braking the fixed positioned elements placement

Signed-off-by: Egor Savkin <es@m-labs.hk>

static/js/shop/options/Notification.jsx

@@ -11,6 +11,9 @@ export function Notification({id, tip, content, sideMenuIsOpen, show, onHide}) {
             overlay={props => <Tooltip id={id} {...props}>{tip}</Tooltip>}
             rootClose={!sideMenuIsOpen}
             onToggle={onHide}
+            popperConfig={{
+                strategy: 'fixed'
+            }}
         >
             {content}
         </OverlayTrigger>