[jeremye]

It seems that there are two different configs that would cause this webmaster mode issue:

1) X-Cart v3.4.14 or below AND Smarty 2.6.2
2) X-Cart v3.5.x AND Smarty 2.5.0.

Is anyone running v3.5.x AND Smarty 2.6.2 and having this issue?

I wonder if X-Cart support would help us, even though they did not officially approve the upgrade to Smarty 2.6.2?

Unfortunately, I don't even receive ANY Javascript errors, so I have no idea where to start.

With the ParentNode issue above, I wonder if the debug console window is open? Do you have a popup blocker? I often get Javascript errors on a website that expects a popup to load, but my blocker blocks it.