Drop a RadRichTextEditor and a WinForms button on a form.
Set the text of the button to "&Activate" and show a message box in the button click handler.
Run the program, and type some text - the button is activated whenever you try to type the letter "a" in the editor.

Workarround: Inherit RadRichTextEditor and override IsInputChar method
protected override bool IsInputChar(char charCode)
{
    return true;
}