The question in this thread is similar to one logged in one of your latest ticket threads. I will copy the answer from my colleague Dilyan here so that the community can take advantage of it:
I prepared a small sample project which I believe satisfies your requirements. For this purpose, I've handled the Loaded event of the parent RadGridView control.
In the Loaded handler, I create a glyph icon, which upon hover shows a tooltip that indicates that the +/- buttons need to be clicked for the rows to be expanded. I suggest this approach because if you decide to display text which has a width wider than that of the default one for the cells which display the buttons, further modifications will be required, which are not straightforward.
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