ContextMenu in a Marker, event rightclick

Hi,

When I right-click opening a contextMenu in a marker, in the first try, this contextMenu stays hidden. But when I right-click in the second try, on the same marker the contextMenu is displayed and a marker is valid. Furthermore, when I right-click in other a marker, in the first try a contextMenu is displayed, but this marker result is null.

Is this a known bug?

Thank you!