SimpleToolWindowPlugin very slow

Hello all,

I am about to write my first IDEA plugin. The HelloWorld plugin worked okay.
Now I am trying the SimpleToolWindowPlugin but it runs incredibly slow.

That's what I did:
1) followed all the steps in http://www.jetbrains.com/idea/documentation/howto_03.html
2) Closed the HelloWorld project
3) unzipped idea-5.1.2-dev.zip into a new directory
4) opened the toolWindow project
5) run the SimpleToolWindowPlugin
6) a new instance of IDEA starts and opens a project
7) On the left there are three buttons: "1: Project" "7: Structure" and "SimpleToolWindow"
8) when I click "SimpleToolWindow" a panel appears with the "Hello World!" label
9) when I toggle three times between "SimpleToolWindow" and Structure,
everythings starts to go dog slow and X starts eating 98% CPU for a while
10) when I toggle between Project and Structure everything works smoothly

Any idea what could be wrong ?

• sun jdk 1.5.0_03

• IntelliJ IDEA 5.1.2 build #4267

• CentOS 4.0, 2.6.9-5.0.3.ELsmp

Thanks,
Maarten