Adjusting luminosity bug on iMac 5K

[whyOwhy]

When adjusting luminosity in VLC 3.0.1 on an iMac 5K, the video stretches to the edge of the screen every time the luminosity keys is pressed.
Pretty annoying. Doesn't happen with VLC 2.2.8.
I think I've had other instances where 3.0.1 had troubles keeping the original format of the video on the imac, but can't remember when. Will post again if it happens.

[whyOwhy]

Up. This is still an issue in 3.0.8.
Still as annoying.

[fkuehne]

Please re-try with 3.0.9 which addresses various video output issues and this could be fixed as a side-effect.