EditHelp is shareware. The registered version has several features not available in the unregistered version, including:
bitmap links
bitmaps with multiple hotspot links
links can execute DLLs and EXEs
layout commands:
indented lists
lines
boxed text
centred text
text commands:
different fonts
different character sizes
coloured text
bold and italic text
browse lists
You can still obtain these features in the unregistered version via the {literal} command - but it's far less convenient.