ToolStrip - how I can make rectangle on the last selected item ?

[Mr. X.]

Hello.
I am using toolstrip.
I want to make rectangle on the selected item only.
How can I do that ?

Thanks

 

[Mr. X.]

Problem solved.
What I have found, that ToolStripItem, which is created by :
ToolBox.items.add("a text" , myImage) is created as toolStripButton, which
has checked component.
I need only one button to be checked, so each time it is checked, I do a
loop for the rest of the toolStripButtons.

Thanks, anyway