Clicking desktop icons in Animated Windows System UI example may not always close application windows

In the Animated Windows System UI example, you can open two different application windows by left-clicking their respective desktop icons. They can then be closed by either left-clicking their icons again, or left-clicking the x button that is part of the application window. If an application window is open, and you double left-click its icon, you can now only close that application window using its x button. Left-clicking the icon will do nothing in this case.

Steps to reproduce:

1. Left-click the icon with a fish on it. Notice that the application window containing a fish will be displayed.
2. Left-click the icon with a fish on it again. Notice that the application window that was open, will now close.
3. Repeat step 1.
4. Double left-click the icon with a fish on it. Notice that the animation of closing the window will start, but the window will instantly open again.
5. Left-click the icon with a fish on it. Notice that nothing happens, not matter how many times you left-click the icon.
6. Left-click the x button of the application window containing a fish. Notice that is will now close. The icon with a fish on it will now act as expected again, until you double left-click it while its application window is open.

Expected behavior:

If an application windows is open, left-clicking its icon should close the application window.

Observed behavior:

If an application window is open, and you double left-click its icon, the application will remain open, but you can no longer close it with the icon. You can only close it with the x button. After closing it with the x button, left-clicking the icon will behave as expected again.