This happen because of the new UIStyle property.
It works as the other stylers. If you want to change the properties to your preferences,
you will first need to change the style to 'tsCustom'.
We will change the behavior in the following update, where the UIStyle will be set to ‘tsCustom’ on creation after getting the initial Office look.
This will give you the newest look, but will also make it possible to change the style to your preferences.
Ok ... thanks
We aim for a release Feb 10 or 11
We've also changed this for TAdvPanel.