I pointed this out in Alex's X3d issues thread, but was told to start another thread about it.
It didn't seem worth it.
It only seems to affect tracks (not busses), and only where the CE has not been used.
As soon as you turn on the CE, the needles appear.
I guess some routine that paints the needle isn't called until the CE is turned on. When it is, the needles appear. It's hardly a show stopper, but would imagine that it is easy to fix.
I imagine that Cake will pick this up, but didn't need another thread to trawl through to find it.
There we are, I've fulfilled Alex's agenda after all.
The workaround is to not look at the CE needles until you need to.