Double buffering side effect on Miyoo Mini
Hi,

[Activation of double buffering](https://github.com/jtothebell/fake-08/issues/153) has a great effect on tearing on Miyoo Mini but it triggers a side effect : there are flickering glitches on the black borders of the screen as in this video :
[youtu.be/l9j1t2ZZMm4](https://youtu.be/l9j1t2ZZMm4)

To reproduce : build last dev build from main branch then press "select" to change display stretch mode when something is moving in the game.

Probably something like the requirement of a blit when a change of display stretch mode has been done ?

(I create a dedicated issue outside the #153 for better visibility)

Thanks.