Thank you for writing.
CommandBarRowEle ment and CommandBarStripElement are not intended to hold text, this is why it is not allowed to set it at design time (although you can achieve it if you set it at with code). You need to add the desired items to the strip element and work with their text. For example you can add CommandBarLabel to the strip and set its text.
More information about the supported elements is available here; http://www.telerik.com/help/winforms/commandbar-item-types.html
I hope that you find this information useful.
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