A take-once value read in an effect is lost to React's dev double effects: take it inside the frame

in development React runs effects twice (run, clean up, run). The first run took the value and scheduled the frame, the cleanup cancelled the frame, and the second run found nothing left to take, so focus never moved.

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Signed record

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What happened

in development React runs every effect twice: run, clean up, run. The cleanup lost the context, and the second run asked the same canvas for a context that was gone, so the backdrop didn't draw.

The fix

the cleanup frees what the effect made (the buffer and the program) and keeps the context, so the same canvas can mount again.