UI personalization can be applied to CMS Desk only. Site Manager cannot be personalized as it is typically used by administrators and developers who need the full rather than a simplified UI.
As for CMS Desk, you can personalize the UI elements in the following parts of CMS Desk. Module names in parentheses show which module represents these parts of CMS Desk:
•CMS Desk main tabs (module CMS Desk)
•CMS Desk -> Content tab (module Content)
•CMS Desk -> Content -> New (Module New)
•CMS Desk -> My desk tab (module My desk)
•CMS Desk -> Tools tab (module Tools)
•CMS Desk -> Administration tab (module Administration)
•WYSIWYG editor (module WYSIWYG editor)
•Media dialog (module Media dialog)
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