+void Layout::push_arrangement(Arrangement &arr)
+{
+ arrangement_stack.push_back(&arr);
+}
+
+Arrangement *Layout::get_arrangement() const
+{
+ if(arrangement_stack.empty())
+ return 0;
+ else
+ return arrangement_stack.back();
+}
+
+void Layout::pop_arrangement(Arrangement &arr)
+{
+ list<Arrangement *>::iterator begin = find(arrangement_stack.begin(), arrangement_stack.end(), &arr);
+ if(begin==arrangement_stack.end())
+ return;
+
+ while(1)
+ {
+ Arrangement *top = arrangement_stack.back();
+ arrangement_stack.pop_back();
+ if(!arrangement_stack.empty())
+ arrangement_stack.back()->arrange(*top);
+ if(top==&arr)
+ break;
+ }
+}
+