This can be a bug. We are working to reproduce and fix it.
Your description is not quite clear. Can you please describe in more detail, what kind of trembling to you see?
What video card do you use? What version of Windows to you use (XP, Vista, Win7)?
What is the exact version of iPi Studio on your computer? Is it 1.0.0.95 or 1.0.0.96 or 1.0.0.97?
We fixed a similar bug with crash on target character import, maybe you just need to upgrade to latest version (1.0.0.97).
You can wait for the fix; alternatively, you can roll back older version. To do this, go to "Uninstall Programs" in Control Panel, select iPi Studio and press "Uninstall/change" button, then select "Restore the application to its previous state".
http://www.ipisoft.com/images/restore_p ... rsion1.pnghttp://www.ipisoft.com/images/restore_p ... rsion2.png