Are Catholics allowed to celebrate the Reformation?

This is going to be published in my local Catholic parish's bulletin this week. >A SPECIAL EVENT: REFORMATION 500 COMMEMORATION > > Wednesday, April 26 @ 7:00pm > > In honor of the 500th Anniversary of the Reformation, > > St. John’s Lutheran Church will host an ecumenical vesper service. Congregations in Evansville will gather to embrace our commonalities. Ministers from the various congregations will be discussing our similarities and differences regarding Holy Baptism and Holy Communion in a relaxed atmosphere, followed by refreshments. This event is in collaboration with our partner congregations in Evansville. The whole community is invited; invite your friends and neighbors of all faith traditions! Has anything changed in the last 500 years that Catholics should be commemorating the Reformation? For some odd reason I thought we were against that...