"Other" glyphs not viewable in Glyphs Mini

In my font, I have a number of Private Use glyphs, plus a number of non-exporting “other” glyphs.

Using Glyphs Mini 2.1.3 (99), from the main Font view, if I double-click on a private-use glyph, this opens the editor window as normal. However, if I double-click on a glyph in the “other” section, neither the glyph itself nor any of the global guidelines are visible, and the glyph name does not appear at the top of the tab.

I have an older version of the font, in which this problem is not happening. The difference between the older version and the newer version is the addition of about 1500 glyphs.

Is this a bug in Glyphs Mini, or a limitation on the number of allowable glyphs? I did not see a maximum number of supported glyphs in the documentation handbook or on the website.

Glyphs files:
http://carolingianrealm.blog/glyphs/Carogine-Italic.zip

This is running on MacOS Mojave, 10.14.6.

Glyphs uses some of the PUA code internally. And because you used so many, there are no left.

What exactly are you trying to do? It doesn’t look right. Those tutorials might help:
https://glyphsapp.com/tutorials/diacritics
https://glyphsapp.com/tutorials/mark-attachment

Thank you for the links. I will try a different approach.