WHY THE WANA AREA?
The 1893 treaty that established the Durand Line as the official border between Afghanistan and Pakistan, was term limited to 100 years. That means that as of 1993 (11 years ago), the Durand Line ceased being the official border between these two countries. A provision in that treaty called for a re-negotiation of the exact boundaries of that border upon the expiration of the treaty. A Tripartite Commission has been formed to do just that.
"Coincidently", it was just one year shy of that treaty expiration date in 1992, that Pakistan installed the Taliban government to power in Afghanistan.
--Boot Hill