I need to build gui for my application in Netbeans (I’m not interested in other solutions, for example Eclipse and its plugins cause my teacher demands my app to be written in Netbeans only).
I created a Netbeans Java project and added JPanel and JFrame form but drag and drop builder doesn’t work. I still see this:

and even if I try to drag (for example), JButton and drop it on JPanel nothing’s happen.
What should I do? Use latest Netbeans 7.1 on Kubuntu 12.04.
My IDE log: http://pastie.org/private/lige9jjnsi2fq7bx08purw
And see also this:

Debian/Ubuntu
This might to be a bug at the moment in the Debian/Ubuntu Version. I found the following two bug reports, that seem to match your bug:
To sum the bug reports up: There doesn’t seem to be a real fix to that yet, but for some people starting NetBeans with the following command is a workaround:
Unfortunately I don’t have a Debian bases system here at the moment, so I cannot test, if it would work for me.
Gentoo
It seems that the same bug also effects Gentoo Linux. I could workaround there by emerging
dev-java/batikand then starting NetBeans with:The versions in this command might need to be exachanged, if you have installed different versions of the applications.