Found in Blender 2.59

In some cases, the property editor does not show properties of an object because they are scrolled out of sight, yet there is no scrollbar, looking like there are no properties available at all.

1) In the properties editor, go to any object related context that extends beyond the window size, so you have to scroll to see all, like Material or Particles (with added PS)
2) Scroll down to the bottom of the context
3) Delete the object whose properties you are currently in
4) Create a new object that can have the same properties like the one you just deleted (e.g. no Lattice when you were in Material tab, since lattices can't have materials)
5) In the properties editor, the new object will display the context that you were in last on the deleted object, also referencing the position you scrolled to. But since there are e.g. only empty Material slots, the contents of the context do not reach down as much as for the deleted object, therefore the tab seems empty unless you MMB-click and scroll or press POS1 to get back to the top or if you're in windowed mode, just move the program window.

This happens especially in Particle(with active PS) and Material context, because they regularly are much longer vertically, but in principle, this could happen in any context (e.g. when adding lots of Custom Properties). Probably this is also depending on available screen space/resolution, so if you can't get it to work on a 30" display, perhaps reducing vertical blender program window size makes the problem more likely to happen.