We need to avoid needless churn in FXNode strands. The problem is that when opacity is changed from 1 to 0, we alter the tree such that we insert an SGComposite node. Once we get back to 1.0, we remove the node. This is good for memory, but bad for CPU time if you have a lot of fading transitions because dynamically modifying the tree is not very cheap (especially if done frequently) and also causes a loss of focus. Rather, when once used, we keep these nodes in the tree.

Note that we might even change this so that we always have these nodes in the tree regardless of if they are used because otherwise we run in focus issues when fading a focusable node out.