I was playing with the track colors setting all the tracks to follow the buss color.
 
this is an existing project and I just used cntr-a to select all the tracks, hold down ctrl and click the track color then right click on the default and select follow buss. Then I changed the buss colors sometimes using the custom colors. I played around with different colors for a while and all was looking good until....
 
I tried to save the project and x3 crashed.
 
I sent off the crash dump and entered my email so I have a ticket.
 
I was not able to duplicate the crash when I reopened X3 I did the same things and saved the project successfully.
 
Just a heads up in case someone else sees this.
 
 
 edit: spelling

Still not able to duplicate this but I wanted to add that the color features are awesome when they work. Hopefully this was a one off situation. I have setup a custom template as usual for new projects using the track matches buss option and can't say enough about how this simplifies working with the tracks and buss's.
 
I love how I can immediately see where everything is going and things are logically grouped together.