draw_output_border = function()
	App.color(Normal_color)
	-- hack: computing based on editor before output exists
	local x1 = Editor_state.left-5-Line_number_padding
	local x2 = Editor_state.right+5
	local y1 = Editor_state.bottom+5+10
	-- upper border
	love.graphics.line(x1,y1, x2,y1)
	love.graphics.line(x1,y1, x1,y1+10)
	love.graphics.line(x2,y1, x2,y1+10)
end