This may actually be a Windows issue... the keys for uninstall are being written to the Wow6432Node of the registry (on a 64-bit machine), and apparently the Programs and Features panel does not read them from there.

The 64-bit installers should be fine (testing one now) since they probably don't redirect the registry writes.

I actually have more than twice as many entries under here than in the main view - mostly Visual Studio components - and none of them appear in the panel. I'll try and ping some people here and find out how to fix it.