The picker paints an opaque frozen frame edge to edge, so the blur and dim
it inherited from the shared qs-overlay rule were compositor work on pixels
nobody sees. It now has its own layer rule.
no_anim is the load-bearing part. Capture.qml unmaps the picker and runs
grim 90ms later, and the default 200ms layersOut fade put the half-faded
picker, dimming and all, into every screenshot.
Gabriel Brown
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