I think what you want to do is use the "select curves as regions" and then select the sketch with the repeating pattern. You'll have a design tree just to the right of the dialogue box and you'll have to expand it to show the sketches within the feature. If your original is on the same sketch, it is also selected.
If there's anything in there that's extraneous to the operation you can delete it from the list.
There's an additional advantage to using select curves as regions because the link is maintained if you update the feature. If you select flat area features you have to re-select in VM each time you update the feature.