Is there any progress on this issue? There is no correct way to have "sample" text on multiline mode, and if the textbox is in multiline so should the sample text as I see it. And of course adding \r\n has its consequences when the font is changed.
At this time the NullText functionality for a multiline RadTextBox is not implemented. However, you make your own implementation, which will give you the same visual results. I have demonstrated it in the sample project attached. The approach concerns setting Text and ForeColor properties of the RadTextBox.
Regarding the "\r\n" escape sequence, you do not need it when setting Text in RadTextBox. The text which cannot be put on the current line will automatically be transferred to a new line.
If you have additional questions, feel free to contact me.
the Telerik team
Check out Telerik Trainer, the state of the art learning tool for Telerik products.