enum ScrollBridge

Where a wheel notch goes when nothing in the view tree wanted it.

The renderer stood aside because a node under the pointer claimed the wheel; if that node and every ancestor then declines, the container around them should still scroll — the notch goes back to whoever owns the scene. In one process that is a call into the engine. Under a compositor the scene is in another process, and a client's own engine has no renderer to hand it to, so the notch was simply dropped: an editor inside a scrolling page pinned the page.

Same shape as ClipboardBridge, DropBridge and ScreenshotBridge, and unset means windowed.