No worries, thanks for finding it! :)
Fortunately this was a really quick fix. The main issue with the start position was related to a change to an underlying function I was relying on to print out the XYZ coordinate as a string to the script code. Long story short, it was putting parentheses around the coordinate which invalidated the script due to incorrect syntax - for example (2, 3, 4) instead of just 2, 3, 4 as it was previously doing.
Also, the other issue relating to editing the script preview appears to be a bug in the text edit UI component I am using. I actually have it marked as disabled/read-only since (at least for now) it's just to show you what the source code looks like, so the copy/paste needs to be disabled also. That would explain why it didn't save since it wasn't expected to be edited. :)
Thanks for the bug report! I'll have the start position fix in v0.3.4, and will look further into the copy/paste bug since that could cause confusion.