I noticed that if there are more than 8 light sources in the model, visual rendering is not correct. What's more important, FlexSim user interface doesn't work correctly after the 9th light source is added.
This is how you can reproduce it: set ambient light to black and delete all light sources but the first one, set it to black, then add 8 more light sources (which will be copies of the first one). As soon as the 9th light source is added, you will see wrong colors in the Perspective view window.
User interfaces breaks in a different way if I add point light source or parallel light sources, but it looks like some kind of memory corruption issue.
Applies to: FlexSim 19.1.0 and earlier versions.