while true do
    local e = {os.pullEvent()}
    if e[1] == "mouse_click" and e[3] >= self.x1 and e[4] >= self.y1 and e[3] <= self.x2 and e[4] <= self.y2 then
        self.oldcolor = self.color
        self.color = self.border.color
    elseif e[1] == "mouse_up" and self.oldcolor then
        self.color = self.oldcolor
        self.oldcolor = nil
    end
    self.render()
end