FACT: Xara has a crippled, out-of-date type-engine.

[gwpriester]

Here is how Illustrator and InDesign handle glyphs.

The drop down menu shows the extended character groups (when present) for each font. Then once you make a selection, the characters for that selection are displayed. In this example discretionary ligatures.

The other thing that needed to be addressed is most of these fonts with the large number of glyphs are OpenType fonts which are not represented in the Fonts Gallery.