aux window - fix setTimeout leak

[andrewkchan]

Fixes #311823

Normally when the window is defocused, the browser will throttle any timeouts set on it. In VSCode there is a concept of aux windows, and timeouts set on the main window must not be throttled when the user is working in the aux window. There is some special code to do this in enableMultiWindowAwareTimeout by monkey-patching setTimeout in the main window + aux windows.

This code contained a memory leak where any call to setTimeout with >0 auxwindows would insert a dispose function into the main window's disposables table and never clean it up, even after calling it. I work on Cursor which is built on VSCode, and our app calls setTimeout something like 400 times per second and this was causing my app to have 230MB+ retained just by the main window disposables table.

[Copilot]

Pull request overview

Fixes a memory leak in the workbench’s multi-window setTimeout monkey-patching so timer disposables don’t accumulate in the main window’s per-window DisposableStore when auxiliary windows are open.

Changes:

• When a timeout disposable runs, it now removes itself from the owning window’s DisposableStore using deleteAndLeak, preventing retained references after disposal.

[Tyriar]

lgtm, timeoutDisposable is added to disposables and then never gets removed for the lifetime of the window.

@bpasero could you check this out?

[bpasero]

Thanks