Operator area_dupli_invoke should not create modal windows.
When I refactored some of the window creation code in D10419: UI: Simplify Window Creation I had intended to not make any behavior changes, but failed in one case. Operator area_dupli_invoke is now creating windows that are set "modal" where they were not before my changes. I didn't notice this because on my platform (Windows) such windows are not treated differently. But on Mac they are treated as modal, which is not correct for this operator.