The Operator dropdown button is not in sync with the Transform buttons.
- Select an object (the default cube for example)
- Click on the Rotate button (Tools tab)
- Rotate the object in the viewport (the Operator dropdown button doesn't change, the previous Operator options are still displayed)
- As soon as you release your mouse button, the Operator changes and displays the options for the button you have just pressed (in this example, Rotate )
I think that the Operator should be in sync with the Transform buttons, and be changed as soon as the user presses on these buttons.