It is important to understand that this application is not in any way trying to patent layout managers in general. Indeed the specification clearly describes existing layout manager systems including Swing, WPF, Qt, Cocoa and others. What it is attempting to patent is a specific method of providing layout management using a logical binary tree structure. Therefore, if one wants to provide prior art to invalidate this patent, you need to find an existing example of a similar scheme. I'm not personally aware of one, but I'm not particularly experienced in this field.
Another thing to consider is that claims as published in applications are very frequently far broader that what might eventually get granted. I looked up the current status in the US Public Pair and the application has received a non-final rejection. In particular Claims 1-6, 15-20, 22, 29 and 10 were rejected as unpatentable over Dyar et al US2016/0092084 A1, in view of Atkins et al US 2010/0275152 A1 published 10/28/2010. Further claims 7 and 21 were rejected as unpatentable over Dyar in view of Atkins in view of Zeidler et al "Constant Solving for Beautiful User Interfaces: How Solving Strategies Support Layout Aesthetics", 2012.
This is not to say it wouldn't be valuable to seek additional prior art, but this doesn't seem to be one of those software patents that is trying to patent common knowledge, and it seems at least at this time that the examiner is doing her job.