Actual:
Keyboard focus order is not logical after opening "Add a category to this page" dropdown.
After opening the added category control , the keyboard focus is moving to the "Add a category to this page" dropdown instead of moving inside the expanded control dialog .

Expected:
Keyboard focus order should be logical after opening "Add a category to this page" dropdown.
After expanding the added category control , the keyboard focus should move to the "Remove" button.

User Impact:
Keyboard only user faced difficulty while navigating the screen as keyboard focus order is not logical .