Hello!

I am very puzzled about ploting with roofit in the windows subsystem for linux(WSL), there is always a white area which I cannot make it filled.

My code is

```
#include "RooRealVar.h"
#include "RooDataSet.h"
#include "RooGaussian.h"
#include "TCanvas.h"
#include "TAxis.h"
#include "RooPlot.h"
using namespace RooFit;
void f1()
{
// Create observables
RooRealVar x("x", "x", -10, 10);
// Create Gaussian
RooRealVar sigma("sigma", "sigma", 5, 0.1, 10);
RooRealVar mean("mean", "mean", 3, -10, 10);
RooGaussian gauss("gauss", "gauss", x, mean, sigma);
// Generate a sample of 100 events with sigma=3
RooDataSet *data = gauss.generate(x, 1000);
// Fit pdf to data
gauss.fitTo(*data);
// M a k e p l o t f r a m e s
RooPlot *frame = x.frame(Name("xframe"), Title("Filled Curve / Blue Histo"), Bins(20));
// D a t a p l o t t i n g s t y l e s
data->plotOn(frame, MarkerColor(kBlue), LineColor(kBlue));
// F u n c t i o n p l o t t i n g s t y l e s
gauss.plotOn(frame, DrawOption("F"), FillColor(kOrange), LineColor(0), FillStyle(3344));
TCanvas *c = new TCanvas("f107", "f107", 800, 800);
frame->Draw();
}
```

When mean=-3，the result is no problem, but mean=3, the result is

I am puzzled for this result about the reason for the triangle area, maybe the question from

```
// F u n c t i o n p l o t t i n g s t y l e s
gauss.plotOn(frame, DrawOption("F"), FillColor(kOrange), LineColor(0), FillStyle(3344));
TCanvas *c = new TCanvas("f107", "f107", 800, 800);
frame->Draw();
```

,but I have changed the value, and no use. What’s more, my output looks no error

```
RooFit v3.60 -- Developed by Wouter Verkerke and David Kirkby
Copyright (C) 2000-2013 NIKHEF, University of California & Stanford University
All rights reserved, please read http://roofit.sourceforge.net/license.txt
[#1] INFO:Minization -- RooMinimizer::optimizeConst: activating const optimization
**********
** 1 **SET PRINT 1
**********
**********
** 2 **SET NOGRAD
**********
PARAMETER DEFINITIONS:
NO. NAME VALUE STEP SIZE LIMITS
1 mean -3.00000e+00 2.00000e+00 -1.00000e+01 1.00000e+01
2 sigma 5.00000e+00 9.90000e-01 1.00000e-01 1.00000e+01
**********
** 3 **SET ERR 0.5
**********
**********
** 4 **SET PRINT 1
**********
**********
** 5 **SET STR 1
**********
NOW USING STRATEGY 1: TRY TO BALANCE SPEED AGAINST RELIABILITY
**********
** 6 **MIGRAD 1000 1
**********
FIRST CALL TO USER FUNCTION AT NEW START POINT, WITH IFLAG=4.
START MIGRAD MINIMIZATION. STRATEGY 1. CONVERGENCE WHEN EDM .LT. 1.00e-03
FCN=2825.41 FROM MIGRAD STATUS=INITIATE 8 CALLS 9 TOTAL
EDM= unknown STRATEGY= 1 NO ERROR MATRIX
EXT PARAMETER CURRENT GUESS STEP FIRST
NO. NAME VALUE ERROR SIZE DERIVATIVE
1 mean -3.00000e+00 2.00000e+00 2.11716e-01 -7.90217e+01
2 sigma 5.00000e+00 9.90000e-01 2.01369e-01 -4.00425e+01
ERR DEF= 0.5
MIGRAD MINIMIZATION HAS CONVERGED.
MIGRAD WILL VERIFY CONVERGENCE AND ERROR MATRIX.
COVARIANCE MATRIX CALCULATED SUCCESSFULLY
FCN=2824.05 FROM MIGRAD STATUS=CONVERGED 38 CALLS 39 TOTAL
EDM=1.10538e-07 STRATEGY= 1 ERROR MATRIX ACCURATE
EXT PARAMETER STEP FIRST
NO. NAME VALUE ERROR SIZE DERIVATIVE
1 mean -2.76714e+00 2.18379e-01 7.34220e-04 -8.64236e-03
2 sigma 5.10682e+00 1.93674e-01 1.26581e-03 4.87329e-03
ERR DEF= 0.5
EXTERNAL ERROR MATRIX. NDIM= 25 NPAR= 2 ERR DEF=0.5
4.770e-02 -2.009e-02
-2.009e-02 3.753e-02
PARAMETER CORRELATION COEFFICIENTS
NO. GLOBAL 1 2
1 0.47485 1.000 -0.475
2 0.47485 -0.475 1.000
**********
** 7 **SET ERR 0.5
**********
**********
** 8 **SET PRINT 1
**********
**********
** 9 **HESSE 1000
**********
COVARIANCE MATRIX CALCULATED SUCCESSFULLY
FCN=2824.05 FROM HESSE STATUS=OK 10 CALLS 49 TOTAL
EDM=1.11281e-07 STRATEGY= 1 ERROR MATRIX ACCURATE
EXT PARAMETER INTERNAL INTERNAL
NO. NAME VALUE ERROR STEP SIZE VALUE
1 mean -2.76714e+00 2.18722e-01 1.46844e-04 -2.80372e-01
2 sigma 5.10682e+00 1.93978e-01 5.06326e-05 1.14789e-02
ERR DEF= 0.5
EXTERNAL ERROR MATRIX. NDIM= 25 NPAR= 2 ERR DEF=0.5
4.785e-02 -2.026e-02
-2.026e-02 3.765e-02
PARAMETER CORRELATION COEFFICIENTS
NO. GLOBAL 1 2
1 0.47740 1.000 -0.477
2 0.47740 -0.477 1.000
[#1] INFO:Minization -- RooMinimizer::optimizeConst: deactivating const optimization
```

Maybe there is something wrong in WSL, I am new in WSL with Xming, and my ROOT is 6.20.

Thank you for you reply!!!