Landscape for Month Year Picker Color Background Issue

[dozy-programmer]

I am having an issue where in landscape mode, there is a rectangle of white in the top right corner of the dialog. I set the background to a different color and for some reason, that part is defaulting to the original color. On a regular phone like a Pixel or a Oneplus 6T, this isn't too much of an issue, but on a tablet, that white portion is large in proportion to the dialog.

On a regular sized device:

On a tablet: