I was copying the code from one script to a new one manually yesterday. I didn't want to spend the effort to export and import, so I just opened a new window and proceeded. After copying and modifying the working code, I ran into some cryptic errors that took some time to understand.
In short, I copied the run code to the trigger window and the trigger code to the run window. This is a simple fix, but it took half an hour to figure out what the error was telling me. I don't know that this is an issue anyone else would come across, but it was mostly confusing because it gave the line number for the error when I was on the run code window and it was actually referring to the trigger code line number.
My request is for there to be either a different window color for the trigger versus run windows and/or a better error message to let you know that the issue is in the trigger/run code. I think a different color background would have prevented me from making the silly copy mistake, but having a debug message that makes a little more sense to point you to the correct location in code would also be helpful.