TH2 Custom Stats?

ROOT
8

Note “h->SetStats(kFALSE); // mandatory (not sure why)”:

{
  gStyle->SetOptStat(); // mandatory
  TCanvas *c = new TCanvas("c", "c", 600, 400);
  
  TH2F *h = new TH2F("h", "TH2F example ", 30, -4, 4, 30, -20, 20);
  Float_t px, py;
  for (Int_t i = 0; i < 25000; i++) {
    gRandom->Rannor(px, py);
    h->Fill(px-1, 5*py);
    h->Fill(2+0.5*px, 2*py-10., 0.1);
  }
  h->SetStats(kTRUE);
  h->Draw("COLZ");
  
  gPad->Modified(); gPad->Update(); // mandatory
  TPaveStats *ps = (TPaveStats*)gPad->GetPrimitive("stats");
  if (ps) {
    ps->SetName("mystats"); // mandatory
    h->SetStats(kFALSE); // mandatory (not sure why)
    // gPad->Modified(); gPad->Update();
    TList *list = ps->GetListOfLines();
    
    // Add a new line in the stat box.
    // Note that "=" is a control character
    TLatex *myt = new TLatex(0, 0, "Test = 10");
    myt ->SetTextFont(42);
    myt ->SetTextSize(0.04);
    myt ->SetTextColor(kRed);
    list->Add(myt);
    
    gPad->Modified(); gPad->Update(); // mandatory
  } else { std::cout << "Error: ps = 0" << std::endl; }
  
  return c;
}