Problem with Inconsistent Display of Parallel Resource Icon

I am getting inconsistent results when I create custom collections to take advantage of the Parallel Resource Icon.

Here is a list of custom collections the only custom collection that do does generate a Parallel Resource Button:

• "Commentaries on John" based on "type:commentary AND (title:John OR type:john) ANDNOT (subject:"1 John" OR subject:"2 John" OR  subject:"3 John" OR subject:"John, 1st" OR subject:"John, 2nd" OR subject:"John, 3rd" OR subject:revelation OR subject:"epistles of John")"

Here is a list of the custom collections that I have created that don't seem to generate the Parallel Resource Button in their respective resources:

• "Greek Grammars" based on "type: grammar AND title:greek"
• "Greek Lexicons" based on "title:Greek AND title:lexicon"
• "Journals" using the query "type:journal" - none of the journals I opened in this collection had the button
• "Luther's Works" using query "title:Luther's Works"
• "OT in NT" based on a manually built collection of the following ten resources
  • Biblical Exegesis in the Apostolic Period
  • A Biblical Theology of the New Testament
  • A Biblical Theology of the Old Testament
  • Commentary on the New Testament Use of the Old Testament
  • Dictionary for the Theological Interpretation of the Bible
  • Dictionary of New Testament Background
  • Evangelical Dictionary of Biblical Theology
  • New Dictionary of Biblical Theology
  • The Right Doctrine from the Wrong Texts?
  • The Use of the Septuagint in New Testament Research
• "Spurgeon's Sermons" based on "title:spurgeon"
• "Systematic Theology" based on "title:"systematic theology" OR title:dogmatic OR subject:"Theology, Doctrinal." ANDNOT title:Magazine"

A few collections have mixed results among its resources:

• "Greek Syntax" based on "title:lexham" plus these resource added manually: Cascadia and Opentext
  • Interestingly with this collection, out of the 19 resources in the collection, different numbers show up for different resources. Opentext does not show up in the list for the button and itself does not display the button when it is opened as a resource. Cascadia and Lexham resources, however, do show the button and are displayed on the list.
• "Primary Sources Biblical Backgrounds" based on a manual list of the following 11 resources (I am starring the ones that lack the Parallel Resource Icon):
  • Apocrypha of the Old Testament by Charles*
  • The Apocryphal New Testament by William Hone *
  • The Apocryphal New Testament by MR James *
  • The Apostolic Fathers: English Translations by Holmes
  • The Apostolic Fathers: Greek Texts by Holmes
  • Lake's Apostolic Fathers in English
  • Lake's Apostolic Fathers in Greek
  • Pseudepigrapha of the Old Testament by Charles *
  • Works of Josephus: New Updated Edition
  • The Works of Flavius Josephus: Greek Text with Morphology
  • The Works of Philo
  • The Works of Philo: Greek Text with Morphology
  • The interesting thing about this collection is that while the Apostolic Fathers, Josephus and Philo all have the icon, they don't list everything from the whole collection. The icon in Lake and Holmes only lists the four resources associated with Lake and Holmes, Philo only lists Philo in Greek and Philo in English, and Josephus only lists Josephus in Greek and Josephus in English. Also, further complicating the plot is that when I experimented with removing Josephus in Greek from the collection, I found that the English translation of Josephus lost its Parallel Resource icon.

I have also noticed that some collections that do not generate the icon also do not allow changing to related resources using the arrow buttons. For instance none of the Greek Grammar or the Systematic Theology resources allow changing to a related resource with the arrow keys. However, the Greek Lexicons while not having the icon do allow resource switching with the arrow keys.

Also, I have the same problems indicated above whether these resources are part of a saved layout, opened within a blank layout, or floated in its own panel.

Apparently creating custom collections is not the only determinative factor related to enabling the Parallel Resource icon.