52a8bea237
On some GPUs/drivers (seemingly nvidia) and screen sizes, VSE vectorscope and sometimes waveform have "garbage" artifacts around them. Root cause unknown (driver bug?), for now similar fix as a while ago in #112665: explicitly draw opaque background (with alpha=1), and then use alpha blending for the scopes texture display on top of that. Pull Request: https://projects.blender.org/blender/blender/pulls/119512