#include <CtrlLib/CtrlLib.h>

using namespace Upp;

#include <TreeGrid/treegrid.h>

struct MyClass : public TopWindow 
{
	typedef MyClass CLASSNAME;
	TreeGrid TG;
	MyClass();
	virtual ~MyClass() {}
};

MyClass::MyClass()
{
	Title("MyClass");
	SetRect(0,0,600,600);
	Sizeable();

	Add(TG.HSizePos().VSizePos());

	TG.AddColumn("Column 1", 200).Sorting();
	TG.AddColumn("Column 2", 200);
	TG.AddColumn("Column 3", 200);

	//indentation is just for readability..
	//AddNode can fail in two cases: a supplied key is already used, and when out-of-memory
	Node N=TG.AddNode(0, "tree-label (column 1-cell)", /*0 => at root of tree */
                             "key (if you want one)", 
                             "column2-cell", 
                             "column3-cell");
                         
		TG.AddNode(N, "tree sub-node label", /*N => parent of new node*/
                              "", /*empty user-key - keys are auto-generated if empty*/
                              "col2-cell", 
                              "col3-cell");

		TG.AddNode(N, "sub label1", 
                              "", 
                              "col2-cell", 
                              "col3-cell"); 

		TG.AddNode(N, "sub label2"); /*no key and you can have blank values*/
			//must give key (even empty string) if you want values
			//empty cells corresponding to the columns will be silently created

	N=TG.AddNode(0, "another tree-label", 
                        "", 
                        "cell2", 
                        "cell3", 
                        "cell4 - you can have extra cells for private data");

		TG.AddNode(N, "tree sub-node label", "", "col2-cell", "col3-cell");

		Node N1=TG.AddNode(N, "tree sub-node label", "", "col2-cell", "col3-cell");

			TG.AddNode(N1, "node n1", "", "value", "value");

		TG.AddNode(N, "A Label", "", "col2-cell", "col3-cell");

	TG.RefreshTreeGrid();
}

GUI_APP_MAIN
{
	MyClass().Run();
}

 //treegrid.h line 141:
	...
	Column& Sorting(); // <<<--- add this
	Column& Sorting(Gate2<const Node&, const Node&> sortfunc); // <<<--- remove =nullptr

	//add this:
	Column& Column::Sorting()
	{
		b_sort=true;
		return *this;
	}