Billed as an operetta because it adheres to that form’s liberal use of spoken dialogue, but like opera buffa due to it’s nearly 2.5 hr running time, Franz Lehár’s “The Mock Marriage” is filled with the delightful elements of both. They tend to be lightweight and a lot of fun, brimming with love triangles, mistaken identity, a bit of avarice and comedy galore. The story takes place in 1904 Rhode Island and concerns the absurd goings on among the wealthy toffs who inhabit that exclusive enclave, with added modern touches like feminism to liven things up. The Hungarian Lehár was the pre-eminent composer of turn-of-the-century “silver age” Viennese operettas, the success of his 1905 “Merry Widow” having launched him to that esteemed position. “Marriage,” its immediate predecessor, is set in the new world, but it might as well be Vienna – the participants act more like European aristocracy than their American wannabe counterparts, and there are a lot of waltzes throughout. The North American premiere, performed in english at the Lobero Theatre, in a collaboration between the UCSB Department of Music and the UCSB Library, was a thoroughly entertaining and musically satisfying production, and of course, love conquered all by the end.