RadRichTextBox uses MEF to load its extensible components - the dialogs in the UI, context menu, etc. All types loaded by MEF are listed here
and I'm afraid there is no way to obtain them with code. My suggestion to you is to add them in your application just before the initialization of RadRichTextBox.
The fact is RadRichTextBox is pretty feature-complete in terms of UI, so we do not introduce new dialogs with every release. On the chance that this happens, it will be noted in the release notes of the version and the respective articles for the control - Changes
and Backward Compatibility
. I'll also forward your feedback to the team and we will consider introducing some mechanism that will fit your scenario.
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