I am able to reproduce the problem in your example page, and we are using version 6.0 of the CuteEditor from mid-July. I can also reproduce the problem in these forums.

I am using Firefox version 2.0.0.6 to test with. Here is a step by step to reproduce:
1) resize the browser window so a scrollbar appears on the page.
2) change the cutesoft editor to "HTML" view
3) press F12 or click the "Fit to Window" button
4) change the view to "Normal" view

At this point, the editor will revert back to it's original size, but firefox still seems to think it is expanded. you cannot scroll up or down the page.