Can you confirm: The simulator code area shows new code, but the actual behavior of the simulated micro:bit is unchanged. Is that right?
What happens when you download/program the micro:bit? Does the behavior shown in the simulator change? Does the micro:bit behave like the old code or the new code that’s shown in the simulator?
Can you share links to some example programs that don’t seem to run? (Instructions to create a share link are here: https://makecode.microbit.org/share).