"That's not your problem" is a cue I developed with Elka, because of course I can't possibly take peoples' advice when they say to keep cues simple. She's smart enough, I feel that simple cues don't always get the point across. Or, they come to mean a broad category, and don't really apply to the next category.
So, while "Leave it" would suffice for most dogs, for Elka, "leave it" refers to items, objects, and wildlife in the yard.
"That's not your problem" applies to other dogs, either in view or barking blocks away. It applies to people walking past on the sidewalk across the street, car doors closing, people coming home next door, etc. The longer phrase seems to assure Elka that yes, I do see the issue, and she can leave it.