How to let seperator height same as text on toolStrip

I am doing the project, a toolstrip on a form, and this toolstrip has a image background. but, I find the seperator is fit on toolstrip's height when toolstrip's dock = full. looks not good.

to control seperator as text's height, you should set toolstrip's padding value.

padding is space between item region and whole toolstrip's client region

 

also, SendKeys.Send("{F1}") will cause F1 keypress