find_comment_index = function(id)
	assert(Global_state.thread.type == 'rows')
	for i,row in ipairs(Global_state.thread.data) do
		assert(row.type == 'cols')
		assert(#row.data == 2)
		assert(row.data[2].type == 'rows')
		if row.data[2].data[1].id == id then
			return i
		end
	end
end