show_tooltip = function(x,y, tooltip_text)
	if not tooltip_text then return end
	App.color(Tooltip_background)
	local w = App.width(tooltip_text)
	love.graphics.rectangle('fill', x,y, w+10, Line_height+10, 2,2)
	App.color(Tooltip_foreground)
	love.graphics.print(tooltip_text, x+5, y+5)
end