private void OnTrackProperties (object o, EventArgs args)
{
if (current_source != null && !RunSourceOverrideHandler ("TrackPropertiesActionHandler")) {
var s = current_source as Source;
var readonly_tabs = s != null && !s.HasEditableTrackProperties;
TrackEditor.TrackEditorDialog.RunView (current_source.TrackModel, Selection, readonly_tabs);
}
}