M4L Patch Slow With Preview On

Blenny's icon

I'm having an issue where my M4L patch is extremely slow with Preview on. It works great with preview off. Any ideas what would be causing this? As I add to the patch, I'm having difficulty debugging because of the slowness with preview. I've searched the forum and can't find any topics on this. If there's an existing post could someone point me to it?

Blenny's icon

Still looking for answers on this if anyone has any suggestions. Thanks.