fix horizontal drawing of wvumetergl

[m0dB]

No description provided.

[m0dB]

@ronso0 do you want me to create a pull request for main as well? And how about your fix? Shall I create a 2.3 pull request for that or will you do that yourself?

[ronso0]

Yep, that fixes it, thank you!

#10978 is only a workaround for the transparency issue, and since #4906 went into main it's only needed there.
It reduces the yellow (Classsic: red) background to a colored border and now that I see it I think that's sufficient to get attention.
It's better that way regardless if you find a fix for the root cause.

[ronso0]

(waiting for green lights, than we can merge)

[ronso0]

@m0dB
btw I'd appreciate a soonish review of #10973