Lots of problems
devhelp is really slow and drives you crazy if you want to use it on a regular basis. Mozilla doesn't display the docs anti-aliased which looks really ugly. In addition, devhelp cannot handle the case where the window is too narrow to display the whole docs, ie. while you usally can still read function descriptions, the arguements aren't visible anymore without scrolling. This is really, really nasty!
I've also noticed, that you cannot search within the api docs, you can only search for function/variable/macro names, but not within previous search results itself.
An open, cross-platform journaling program.
A scientific plotting package.