Hi,
The short answer to your question is that you need to add extra nodes to the taxiway along the bottom and turn off the edge line on those short segments too. FS extends the lines *from both directions* for quite a distance, and that is what you are seeing - the edge lines from the bottom taxiway extending up along the vertical taxiways.
While AFCAD does show this problem, ADE does not. It does not extend the drawing of the edge lines up the sides of the vertical taxiways, as it probably should.
I tried adding these extra nodes and it does work, but I saw some visual anomalies. So I took the advice above and checked out ADE9 vs AFCAD.
Here is the arrangement in AFCAD:
All looks OK. I left the edge lines on the bottom taxiway outside of the curves to show something later.
Here it is in FS9:
Almost all correct, except for a few things. There is a "jump" in the line along the bottom edge line, for some reason. The outside segment's edge lines are not at the edge of the taxiway, but about 10 feet in from that. And the top edge lines are not showing for the outside segments of the bottom taxiway.
Now we'll do it in ADE9:
As you can see, it looks the same as AFCAD, basically.
Now let's see what it displays in FS9:
Well, we have a different problem (sort of) than in AFCAD. The bottom edge line of center part of the bottom taxiway doesn't have that "jump" in it, so that's good. And the top edge lines are showing for the outside segments, also good. But the left side of the horizontal taxiways have all edge lines placed about 10 ft from where they should be (all taxiways are 100 ft wide).
So there are still some drawing errors in ADE9, and there are problems translating that into FS9 for both programs.
Hope this helps,