Transparent segments have been a well known challenge for accounts of patterns of long distance agreement, such as vowel and consonant harmony. Two standard ways to account for transparency are autosegmental feature spreading with underspecification (e.g. Kiparsky 1981; Steriade 1987) and Agreement by Correspondence (ABC; Walker 2000; Walker & Rose 2004; Hansson 2001). Both, however, fail to derive the multiple instances of transparency encountered in Tsilhqút'ín (Cook 1993; 2013). Here, non-retracted dorsals act both as transparent and as opaque to the process of vowel retraction, depending on which side of the trigger, a retracted sibilant, they are located. On the other hand, both retracted and non-retracted dorsals are transparent in sibilant harmony, in which sibilants are forced to agree in retraction. I propose a superset approach that combines feature spreading and underspecification with ABC: All dorsals are transparent in sibilant harmony, because they are outside the correspondence relation. At the first step of the derivation, non-retracted dorsals are not specified for retraction, allowing them to be transparent to regressive retraction. At a later step, they are negatively specified and hence able to block progressive retraction.