Density plot are not shown, while mesh plots are fine

Dear all
After compiling and installing FreeFem I found that density plots are not shown, while the mesh plots are fine. The FreeFem warning is
Plot:: Sorry no ps version for this type of plot 11

The system is Ubuntu 20.04.
I’ve installed freeglut3 from Ubuntu repository, though which gglut returns binary from FreeFem installation library.

Here is the end of ./reconfigure prompt

configure: WARNING: unrecognized options: --enable-downloads
configure:   FreeFEM used download: yes 
configure:   --  Dynamic load facility: yes 
configure:   --  ARPACK (eigen value): yes 
configure:   --  UMFPACK (sparse solver): yes 
configure:   --  BLAS: yes 
configure:   --  with MPI:     yes
configure:     --  with PETSc: yes / PETSc complex: yes 
configure:     --  with SLEPc: yes / SLEPc complex: yes 
configure:     --  with hpddm: yes 
configure:     --  with htool: yes 
configure:     --  with bemtool: yes (need boost: yes and htool: yes) 
configure:   --  without libs:  
configure:   --  without plugins:  
configure:     progs: FreeFem++-nw bamg cvmsh2  FreeFem++-mpi ffmedit ffglut 
configure:       use of download freeyams  see 3rdparty/yams/freeyams.2011.02.22 (suface mesh adaptation)  
configure:       use of download mmg3d (v4)   see 3rdparty/mmg3d/mmg3d4/LICENCE.txt  
configure:       use of download mmg  see 3rdparty/mmg/mmg-sources/LICENSE 
configure:       use of download parmmg  see 3rdparty/parmmg/parmmg-sources/LICENSE 
configure:       try to download: bem yams nlopt mumps_seq mshmet parmmg mmg mmg3d ipopt 
configure:       use of download boost        see 3rdparty/boost/LICENSE_1_0.txt  
configure:       Please run "3rdparty/getall" to download all necessary packages before running make

Have no idea how to fix it, please, help!

As usual: no script to reproduce the warning/error => almost impossible to help you out.

Sorry, I withdraw the question. It’s my error. While making debug script I’ve found out that the warning was related to the ColorScheme=2 option in the plot function. And after another recompile all the plots are shown.