I'm guess your question regards the following sentence "quite apart from Park Cities, the announcement of the President's murder had inspired eleven separate acts of disrespect in the public schools of Dallas proper."
Park Cities refer to two communities in Dallas County, Texas (Highland Park and University Park), which are surrounded by the city of Dallas.
In American, we often call the communities that are not technically part of the jurisdiction of a city by the name of the dominant city, but when we want to be very technical and specify the city itself (rather than close communities nearby), we say the city proper. So while many people will consider the Park Cities close enough to Dallas to call them Dallas as well, to be technical and precise and refer only to the City of Dallas, then we say "Dallas proper."
So the whole sentence means, "leaving aside the Park Cities, the president's assassination inspired eleven acts of violence within the City of Dallas (that is, the technical definition of Dallas, rather than including all the communities that are geographically close enough to Dallas to be commonly called "Dallas").
Hope this was helpful.