for( Track *track=first; track; track=track->next ) {
if( track->is_hidden() ) continue;
for( Edit *edit=track->edits->first; edit; edit=edit->next ) {
for( Track *track=first; track; track=track->next ) {
if( track->is_hidden() ) continue;
for( Edit *edit=track->edits->first; edit; edit=edit->next ) {