Thank you for your update.
We have analyzed your sample all are working fine at our end, MetroForm1 title bar backcolor is displayed in blue, and MetroForm2 title bar is displayed in white because you set the back color as white in your sample.
Please find the below screen shot.
If you are still facing the issue, please modify the provided sample. It will helps us to investigate further and provide earlier prompt solution.
Farjana Parveen A