Hi Bryant,
I am afraid, we have not implemented this feature yet:
Add support Customizing Font and ForeColor of the Docking window caption when ThemesEnabled=true .
I have once again reported to the development team about this and we will try to implement this feature as soon as possible.
You could track the status of the feature request in the above link. Please let me know if you have any questions.
Thanks for your interest in Syncfusion products.
Regards,
Vijay