The NetBeans plugins page doesn't render correctly using JDK7.
Specifically, the contents of the left-hand pane show as blank even when there is content.
Reloading the contents seems to fix the issue. i.e. by using "Reload catalog" or "Add plugins"
JDK 1.6.0_21 does not exhibit this behaviour.
FYI, I also re-tested with JDK7 build 110 and the issue is still present.
If you claim that JDK6 is OK, but JDK7, then we shall report a bug for JDK. Assigning to Tonda who has access to internal bugster.
*** Bug 192668 has been marked as a duplicate of this bug. ***
Another workaround is sorting the list of modules by clicking on one of the table headings.
*** This bug has been marked as a duplicate of bug 194407 ***