Thank you for writing.
We are aware of the issue you are experiencing. We have it logged in our Feedback portal under the following link - Feedback item.
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Until the issue is resolved you can set the BackColor property of the affected controls to Color.White. The issue here is caused by the fact that the back color of the control is set to transparent and when it is blent with the colors above it it acts as black as its R, G, B components are 0.
I hope this will be useful. Should you have further questions, I would be glad to help.
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