Hello!
One thing I've found is putting calls inside static functions blows things up pretty quickly. When it was just one call per script file I was able to update every 200ms with no problems, but you get like a Button constructor going and then throw some live updates with various arg counts in some onMouseEnter, onMouseClick, draw, doAction etc functions and it crashes the entire app immediately lol
Please email me a sample project that reproduces the issue - any issue that ends up in "Runner exited with non-zero status" is a GameMaker bug and is best filed sooner than later.
This would be great as a built-in feature! Maybe a toggle for auto or manual updating because there are times where you're doing tiny GUI polish adjustments and don't want to have to press a button to update...
Ctrl+S is intended as the update button, but I can look into adding an option that auto-disables the "live" version of function after it errors (so that you would edit it to not error and save to reload).