TBox not showing

[bethlong06]

I want to draw a TBox over my 2D histogram. Without setting the fill color to transparent, it created a grey box over the histogram, but I just want a transparent box with a red outline.
Can someone tell me what I’m doing wrong?

  TBox* b = new TBox(30,30,70,70);
  b->SetLineColor(kRed);
  b->SetLineWidth(2);
  b->SetFillColorAlpha(0,0);
  
  TCanvas *c1 = new TCanvas("c1","c1",900,700);
  hSChPVetoSwumChVsEVetoSwumCh->Draw("colz");
  hSChPVetoSwumChVsEVetoSwumCh->SetTitle(";PVetoChID;EVetoChID");
  //  l->Draw("same");
  b->Draw();//"same");
  
  c1->SetRightMargin(0.10);
  c1->SetLeftMargin(0.08);
  c1->SetTopMargin(0.0351);
  c1->SetBottomMargin(0.075);
  c1->SetBorderMode(1);
  c1->SetHighLightColor(0);
  c1->Modified();
  c1->Update();

  double x1=0.72;
  double x2=0.90;
  double y1=0.80;
  double y2=0.965;

  TPaveStats *s1 = (TPaveStats*)hSChPVetoSwumChVsEVetoSwumCh->FindObject("stats");
  s1->SetName("1");

  s1->SetX1NDC(x1);
  s1->SetX2NDC(x2);
  s1->SetY1NDC(y1);
  s1->SetY2NDC(y2);

  c1->Modified();
  c1->Update();

[dastudillo]

Try:

  //b->SetFillColorAlpha(0,0);
  b->SetFillStyle(0);

https://root.cern/doc/master/classTAttFill.html#ATTFILL2

[bethlong06]

Thank you!