I just realised that I did not explain why pre-1.5 versions of Creative Docs .NET used so much memory. The reason is simple: in order to be able to provide information about the fonts installed on the system, the framework loaded all fonts in memory (full font load, not just the name table). This consumes a huge amount of memory... In the 1.5 version, the application builds a font cache (which requires all fonts to be loaded once); it subsequently only needs to load the information from the cache, which is much faster and needs only a few kilobytes for every font.
When the font list changes (a new font is added or an existing font is removed), the application will rebuild the cache. When this happens, a message shows up in the splash screen.