Does that make this a bounded control? Spinners blur the difference between bounded and unbounded controls. Using either of the two small arrow buttons enables a user to change the value in the edit window in small, discrete steps.

• 微调控制项混淆了有界控件和无界控件之间的区别，使用两个小箭头按钮之一可以使用户以离散的小步改变编辑窗口中的数值。