Reorder Rows - Datatable/treetable

Is there an option to move rows up/down on a button click. Rather than just drag & drop?

Yep, there is an API for moving rows, you can place a buttons ( on the page or in each row ) and call the related API from onclick handlers

http://docs.webix.com/api__datamove_moveup.html

Does this work with in branches on a treetable?

moveUp, moveDown will work for plain data sets only, but there is move api, which will work for all components, including TreeTable

http://docs.webix.com/api__treedatamove_move.html