1. A method comprising: receiving, by a processing device, a request for a user interface (UI) document comprising a first set of media items, wherein a set of identifiers is associated with the UI document, the set of identifiers comprising a page identifier for the UI document and one or more identifiers of the first set of media items; obtaining, by the processing device, an identifier list for a second set of media items in a social share included in the UI document; comparing the set of identifiers for the UI document with the identifier list for the social share to determine one or more media items in the second set of media items that are represented on the UI document; updating the identifier list by removing identifiers of the one or more determined media items that are represented on the UI document; and modifying the UI document to provide a representation associated with a first identifier from the updated identifier list for the second set of media items of the social share.
2. The method of claim 1 , further comprising: obtaining an additional identifier list for a third set of media items in an additional social share included in the UI document; comparing the set of identifiers for the UI document with the additional identifier list to determine one or more additional media items in the third set of media items that are represented on the UI document; updating the additional identifier list by removing additional identifiers of the one or more determined additional media items that are represented on the UI document; and modifying the UI document to comprise an additional representation associated with an additional identifier from the updated additional identifier list for the third set of media items of the additional social share.