You may find attached a sample project where I tried to reproduce the behavior you write us about. Everything is working as expected on my side - both RibbonView and its controls get their style from Windows8 theme. Could you please try to compare your project with the one I'm sending and see if there is any difference in the resource dictionaries you are merging (see App.xaml)? Are you applying any custom style to the RibbonButon-s? If the problem still persists please send us a runnable version of your project where this is reproducible and we'll inspect locally what is causing it.
Please note that customers are not allowed to attach projects in our forums. This is why I would like to ask you to open a new support ticket. Please make sure that you set its Product field correctly. By doing so you will ensure that your case is handled in the best and fastest way taking advantage of your enterprise account.
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