that's TAL-U-NO-LX in the screenshot, right? Bit self-defeating as an example. That UI is a skin. Fixed bitmap, every knob position and hitbox hardcoded, window can't be resized at all. I don't know offhand whether TAL is on vstgui or juce, but it doesn't much matter, with juce you write resized() by hand and chop up a rectangle with removeFromTop/removeFromLeft until you run out of controls. Either way there's no layout algorithm in there. It's what you end up with when you don't have one...
Photoshop is a strange pick too. The extension layer was CEP, which is literally Chromium, and UXP that replaced it ships flexbox. There's a browser version now as well.
Photoshop is a strange pick too. The extension layer was CEP, which is literally Chromium, and UXP that replaced it ships flexbox. There's a browser version now as well.
No negativity, but I feel biased towards CSS ;)