Thank you for writing.
property is inherited from RadControl
. However, RadTextBoxControl
is an input control and it is not designed to display images. That is why this property is not relevant to it.
I have logged it in our feedback portal. You can track its progress, subscribe for status changes and add your comments on the following link - feedback item.
I have also updated your Telerik points.
I hope this information helps. Should you have further questions I would be glad to help.