Pre release versions such as 1.4, 1.5, 1.6.3 and 1.7.1 do not appear in the launcher even when the box next to development versions is checked.

Steps to reproduce:

1. Go to the minecraft launcher
2. Click on edit profile
3. check the box that says Enable experimental development versions
4. click on the arrow next to where it says use version.
5. Notice that all the pre release versions are not there.