+ bool ok = false;
+ const set<Track *> &stracks = selection.get_tracks();
+ for(set<Track *>::const_iterator i=stracks.begin(); (!ok && i!=stracks.end()); ++i)
+ {
+ const vector<Track *> &links = (*i)->get_links();
+ for(vector<Track *>::const_iterator j=links.begin(); (!ok && j!=links.end()); ++j)
+ ok = !*j;
+ }
+
+ if(ok)
+ mode = EXTEND;
+ else
+ signal_status.emit("No free endpoints");
+
+ return ok;