Think about resource management

[guest]

It is very easy to get a memory leak. For example these buttons will never get freed:

    replicateM_ 1234 $ do
        b <- buttonNew
        onStateChanged b $ \_ -> widgetGetSize b >>= print

You can correct this example with eventGetWindow, but that doesn't apply to signals.

The memory leaks in a typical app are small. However, avoiding these leaks may involve API changes so it's important to think about. I suggest, at least, an explicit "objectUnref" action that cancels the finalizer. Then app writers can take care of memory management.

As a nicer API, since a UI is just a tree, perhaps Containers could automatically manage the refs for their children.

[axel]

There is the function widgetDestroy in Widget but there should be an equivalent function in Object.