The tl;dr version is the "ShowTracks" simply populates the field %trigger with a string by default. In this case ShowTracks. You could just leave it blank as "". You need the two quotes to identify it as a string.
Your conditional statement shouldn't use "ShowTracks" anymore but "ShowYOURCHARACTERNAMETracks". For each character.
Long version:
I believe the intent was that you set in the sidebar each characters appropriate globalevent for showing tracks. So in the portion of the script that says EXTERN STRING:%trigger="ShowTracks". %trigger is the variable you set in the sidebar. Which should match the characters name.
ShowBobTracks is the one Zoltan picked.
So your story editor should have separate conditionals for each character. The globalevent "ShowTracks" wouldn't show all characters, it would show none. Since the script is looking for the specific string you put in the sidebar. Unless you keep the conditional for "ShowTracks". I'd probably get rid of it and just use them all individually.
When you use EXTERN STRING:%trigger="ShowTracks" you can replace "ShowTracks with "ShowBobTracks" the "ShowTracks" part is what the script will check for. If you keep it the same and don't remove your conditional for "ShowTracks" then it will always show all characters tracks.
EVENT Appears
ON
OnGlobalEventSet("ShowBobTracks")
ACTIONS
SetVisible(__ME,1)
^That is what the script will be if you change it in the sidebar. You do it on the right side pane during the process of adding the script. Not afterward.
This is where:
![[Linked Image]](http://i.imgur.com/n6Al1Yf.png)