Edited Issue: IsReadOnly and FormatBar-Visibility [21165]

__The FormatBar of the RichTextBox is visible (or "can be used") if the IsReadOnly-Property is true.__

This makes no sense, because I can not edit the text. And it seems to be that there´s no chance to prevent it. I tried to bind the FormatBar-Visibility to the IsReadOnly-Property but it does not work (I´m sure it´s because the Control sets the Visibility to true internally).