Invoking RadRichTextBox.Focus method actually transfers the focus directly to the internal TextBox. I guess this is what you mean by "1. Setting the focus by code doesn't seem to work" - yes, the actual focused element is not RadRichTextBox anymore.
For 2., the default Ribbon UI is bound to RadRichTextBox using RichTextBoxCommands, most of which internally invoke RadRichTextBox.Focus after executing the main action. This is to ensure that the focus is immediately returned the editor, where the used can continue typing/executing commands.
If you have specific problem implementing the desired scenario, you can open a support ticket and upload a sample solution demonstrating it - we may be able to suggest you a solution.
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