Currently, the compose sequence table is displayed using Lucida Sans Unicode (which should be available on all systems in one version or another).
Some characters - e.g. less common fractions - are not present in this font.
If a recent version of MS Office is installed, Arial Unicode MS will be available, which contains these characters.
Under other circumstances, another sensible unicode font may be available.
Add code to AllChars to choose the 'best' available unicode font to display its character table.
For example, provide a list of fonts sorted by # of unicode chars supported, and use the first font from that list.