Permanently disabling throttling for background work can undermine resource policy. Never relaxing it can prevent a site from committing native input through a frame callback. I treat the short input interval as a transaction that retains the previous setting and restores it afterward.
Read the previous setting instead of guessing what to restore
Act reads getBackgroundThrottling, checks task state, temporarily sets throttling false and enables page focus emulation. It does not assume the previous value was true and unconditionally force true on exit. Reading the setting first lets a differently configured caller return to its actual prior state.
Focus emulation differs from activating an operating-system window. The existing browser need not be brought in front of another application. That exception creates no permission to input on arbitrary pages: actNow still performs current target, document and occlusion checks. Temporary rendering conditions support an authorized action rather than replacing its validation.
Cleanup belongs in finally rather than after success alone
Restoration lives in finally, so actNow success, occlusion failure and cancellation all pass through cleanup. Focus emulation is disabled only if enabling succeeded, and destroyed contents are checked before further native operations. Invalid released objects are not manipulated blindly.
Failure to disable emulation is caught so cleanup can continue and attempt restoration of throttling. That does not freshly verify every possible destroyed-object or failed-disable outcome. The presence of finally is not proof of restoration under every imaginable failure. I distinguish the cleanup attempted by code from conditions actually covered by tests.
Give the site a bounded opportunity to commit its next frames
After native input, a site may commit state in requestAnimationFrame. Cleanup waits for two frame callbacks or a 150-millisecond timer fallback, with a bound on the evaluate request itself. Navigation or a disappearing frame must not leave cleanup waiting indefinitely.
This does not expose hidden nodes through CSS or secretly assign values into the DOM. It gives the site's own input and painting handlers a bounded opportunity to proceed. The end of that wait also does not establish remote storage completion. Exact input verification and business-result checks retain their own later responsibilities.
Reading and input exceptions have different lifetimes
VerifyField bypasses the native-input transaction and remains a reading check. Observe has another exception when a complete document has dialog evidence but no readable elements: temporarily relax throttling for a bounded painting opportunity, then restore its prior setting.
It sends no extra click or wheel event to make the observation readable. This is not the same operation as input focus emulation. Both temporarily change a setting, but their entry conditions, actions and restoration locations differ. Keeping each exception inside its own lifetime prevents a local workaround from silently becoming a permanent global setting.
Tests compare hidden and throttled state as well as output
The owned background-input test checks the iframe result and exactly one commit, then compares hidden/throttled state with its starting values. It repeats the preservation comparison after an overlay-induced failure. A correct result obtained by bringing the person's window forward would not satisfy that preservation contract.
I reviewed these sources and controlled tests without hiding an original window or sending fresh native input. The shared cache example implements no focus or rendering transaction. Reuse the ordering of reading prior state, narrowing the execution interval, cleaning up on success and failure, and checking preservation, rather than adopting a blanket setting that disables throttling everywhere.