The partial-dict hardening in d632febf made set_value call
control.set_value() for every band unconditionally. A per-slider
write returns a single-key result dict, so completing one write
re-rendered all 10 sliders from setting._value. Any slider the user
had dragged but whose 0.5s debounce hadn't fired yet got reverted to
its old value — and the subsequent debounce then read that reverted
value and dropped the user's change.
Restore the original behavior: only set sliders present in the result
dict; for the rest, read stored.get() for the tooltip but leave the
widget alone. Keeps the KeyError-safe .get() from d632febf.
d800fc4c54