If Abbas pins down the borders, the construction becomes irrelevant. The settlers inside the to-be-Palestine may want to keep building and try and prevent Palestine. But their funding will dry up. This is a primary reason Netanyahu doesn't want to talk borders. It dries up his raison d'etre.
Labor court orders Jerusalem light rail operators to return to work (Haaretz)
from the article: 'Settlement freeze biggest obstacle to direct talks'