NetBeans GUI builder: "loading..." message

Question

Sample project from the NetBeans tutorials set contains only one Swing form (empty JFrame), compiles and runs fine, but I can't change layout of the form and add elements in it with the NetBeans GUI buider since it shows only empty placeholder with single "loading..." message. Any clues how to fix it would be highly appreciated.

Kubuntu 12.04, Openjdk 1.7, NetBeans 7.0.1 with active GUI designer plugin.

Log file contains an error

SEVERE [org.openide.util.RequestProcessor]: Error in RequestProcessor org.netbeans.modules.form.FormDesigner$PreLoadTask

Answer 1

KNOWN BUG in Designer marked as done (Netbeans 7.0.1 GUI editor is not loading).

Get a new version from netbeans.

Seems to be the same problem.

reported: ... All my projects are using SWING-components, and when I'm clicking on "Design" switcher, in order to make changes in GUI, it is showing label "loading" and I get following error: ...