what caused texting leaders to meet at the constitutional convention of 1836?

There seems to be a misconception or typo in your question, as there is no known historical event called the "Constitutional Convention of 1836" where texting leaders would have met. The Constitutional Convention of 1836 refers to the meeting held in Washington-on-the-Brazos, Texas, where delegates gathered to draft a new constitution for the Republic of Texas. Texting did not exist in 1836 as it is a modern form of communication.