Running `example/simple_example_1/2/3.py` render issue on Linux
When running the example file simple_example_1/2/3.py in the example folder, the rendered popup window is just blank, while running the 'flatland_2_0_example.py` is showing the generated railway and animation correctly.
On Windows machine, everything seems to be fine.
Tried to play with the gl parameter, but no luck.
OS: Ubuntu 18.04 Flatland: newest from git.