MAYBE_UNUSED static const char * EVENT_PLUGIN_LOADED = "PluginLoaded";
/// The active document becomes another one
MAYBE_UNUSED static const char * EVENT_DOCUMENT_CHANGED = "CurrentDocumentChanged";
+/// All documents closed
+MAYBE_UNUSED static const char * EVENT_DOCUMENTS_CLOSED = "AllDocumentsClosed";
/// Event ID that order of objects in group is changed,
/// so, tree must be fully recreated (movement of feature)