Fix styled switch-back repaint

internal/app/session.go

@@ -428,6 +428,18 @@ func (s *Session) SerializeChild(id string) ([]byte, error) {
 	return em.SerializeVT()
 }
 
+func (s *Session) StyledSnapshotChild(id string) ([]byte, error) {
+	c := s.FindChild(id)
+	if c == nil {
+		return nil, fmt.Errorf("no such child %q", id)
+	}
+	em := c.Emulator()
+	if em == nil {
+		return nil, fmt.Errorf("child %q has no emulator", id)
+	}
+	return em.StyledScreenVT()
+}
+
 func (s *Session) SnapshotChild(id string) (string, vt.CursorState, error) {
 	c := s.FindChild(id)
 	if c == nil {