+ // In one traversal of the region view list:
+ // - Build a list of region views sorted by layer
+ // - Remove invalid views from the actual region view list
+ RegionViewList copy;
+ list<RegionView*>::iterator i, tmp;
+ for (i = region_views.begin(); i != region_views.end(); ) {
+ tmp = i;
+ tmp++;
+
+ if (!(*i)->is_valid()) {
+ delete *i;
+ region_views.erase (i);
+ i = tmp;
+ continue;
+ } else {
+ (*i)->enable_display(true);
+ }
+
+ if (copy.size() == 0) {
+ copy.push_front((*i));
+ i = tmp;
+ continue;
+ }
+
+ RegionViewList::iterator k = copy.begin();
+ RegionViewList::iterator l = copy.end();
+ l--;
+
+ if ((*i)->region()->layer() <= (*k)->region()->layer()) {
+ copy.push_front((*i));
+ i = tmp;
+ continue;
+ } else if ((*i)->region()->layer() >= (*l)->region()->layer()) {
+ copy.push_back((*i));
+ i = tmp;
+ continue;
+ }
+
+ for (RegionViewList::iterator j = copy.begin(); j != copy.end(); ++j) {
+ if ((*j)->region()->layer() >= (*i)->region()->layer()) {
+ copy.insert(j, (*i));
+ break;
+ }
+ }
+
+ i = tmp;