That means "something" is triggering an assertion. When in visual studio you don't get the grey popup. Try launching the game without a debugger attached.
I pushed a fix for it.
The game serializes all the javascript components, and in your case:
TimerTick = function()
{
this.UpdateColor();
};
Should have been:
TimerTick()
{
this.UpdateColor();
};
It's possible OneDrive plays a trick with 0 A.D. depending on how your documents are configured on Windows. Another solution if you want to keep everything at the same place is to run 0 A.D. with the -writableRoot command Then everything will be stored in %appdata% next to the game.