open_thread = function(filename)
	local font = love.graphics.getFont()
	local em_width = font:getWidth('m')
	Global_state.root = load_subtree(filename, Margin_left, em_width)
	Global_state.root.top = Menu_bar_height + Margin_top
	-- HERE: Cursor_node needs to be set at the Surface level of abstraction
	--Cursor_node = Global_state.root
	love.window.setTitle('pothi.love - '..Global_state.root.id)
end