Popup with TextInput never garbage collected

In the attached sample application, we use a button to create a popup. That popup has a TextInput and a Button. If you enter text in the text input and click the button, we close the popup.

If you take a memory snapshot after the popup has been closed, it still remains in memory. If you go through this cycle again and create another popup and close it, it keeps acrueing instances.

If you don't focus into the text input, you don't get the memory leak.

This was documented before here (https://issues.apache.org/jira/browse/FLEX-20312) but the issue is still reproducible in 4.8 and I don't know of any workarounds.