Faint somas from rtneuronApp on Ubuntu 18.04.1
Issue on Ubuntu 18.04.1:
When loading the circuit with just the soma I see the following image, with the soma (or whatever) very faint at the center of the image. When I zoom in, it gets even fainter:

That's typically due to compilation errors in the GLSL shaders. Is there anything printed in the console? Do you happen to have an AMD or Intel graphics card?
It seems to be an INTEL graphics card, and I see this following additional output (after start_app()):
GEOMETRY glCompileShader "geom/sphere.geom" FAILED
FRAGMENT glCompileShader "shading/phong_sphere.frag" FAILED
FRAGMENT Shader "shading/phong_sphere.frag" infolog:
0:24(12): warning: extension `GL_EXT_geometry_shader4' unsupported in fragment shader
0:25(12): warning: extension `GL_EXT_gpu_shader4' unsupported in fragment shader
0:30(1): error: syntax error, unexpected NEW_IDENTIFIER
glLinkProgram 0x7f7a28239750"geom/sphere.vert, geom/sphere.geom, geom/default_color.vert, shading/phong_sphere.frag, shading/phong.frag, main.vert, main.frag, " FAILED
Program "geom/sphere.vert, geom/sphere.geom, geom/default_color.vert, shading/phong_sphere.frag, shading/phong.frag, main.vert, main.frag, " infolog:
error: linking with uncompiled/unspecialized shader
Warning: detected OpenGL error 'invalid enumerant' at After Renderer::compile
file:///tmp/.mount_rtneuroL2AZJ/usr/local/lib/python3.7/site-packages/PyQt5/Qt/qml/QtQuick/Dialogs/DefaultFileDialog.qml:210:25: QML ListView: Binding loop detected for property "model"
Gtk-Message: 10:53:23.160: GtkDialog mapped without a transient parent. This is discouraged.
16689 More than one subnetwork found, ignoring extra ones.
16691 Removing mesh-based models from level-of-detail list
failed
In [3]: GEOMETRY glCompileShader "geom/sphere.geom" FAILED
VERTEX glCompileShader "geom/reported_variable_at_soma.vert" FAILED
VERTEX Shader "geom/reported_variable_at_soma.vert" infolog:
0:24(12): warning: extension `GL_EXT_gpu_shader4' unsupported in vertex shader
0:29(23): error: syntax error, unexpected NEW_IDENTIFIER, expecting '{'
FRAGMENT glCompileShader "shading/phong_sphere.frag" FAILED
FRAGMENT Shader "shading/phong_sphere.frag" infolog:
0:24(12): warning: extension `GL_EXT_geometry_shader4' unsupported in fragment shader
0:25(12): warning: extension `GL_EXT_gpu_shader4' unsupported in fragment shader
0:30(1): error: syntax error, unexpected NEW_IDENTIFIER
glLinkProgram 0x7f7a2826b510"geom/sphere.vert, geom/sphere.geom, geom/reported_variable_at_soma.vert, geom/simulation_value_to_soma_color.vert, geom/soma_color.vert, shading/phong_sphere.frag, shading/phong.frag, main.vert, main.frag, " FAILED
Program "geom/sphere.vert, geom/sphere.geom, geom/reported_variable_at_soma.vert, geom/simulation_value_to_soma_color.vert, geom/soma_color.vert, shading/phong_sphere.frag, shading/phong.frag, main.vert, main.frag, " infolog:
error: linking with uncompiled/unspecialized shadererror: linking with uncompiled/unspecialized shader
Warning: detected OpenGL error 'invalid enumerant' at after RenderBin::draw(..)```
I have a laptop with an Intel graphics card where I've seen this errors before. I have to check if I can downgrade the requirements, but I can't think of any other simple solution. Can you run glxinfo on a console and tell me the list of GL extensions supported in your graphics card?
I will need to test the latest suggestion on my laptop. I plan to do this on 16 Jan 2019.