Better icon for 'Show more symbols'
The current icon for the 'Show more symbols' dialog in the Palette is anti-intuitive in my opinion. The '???' first seemed like a rendering problem (was I missing an icon perhaps? Broken font or installation?).
A better icon which is normally used for this type of dialog would be '...'. Here is a mock-up done with GIMP:
This is obviously a very minor issue, but a clearer symbol can help people make more sense of the interface and discover this option.