My Forms editor displays incorrectly in IE. When I try to configure controls, the view of the form is limited - see attachment. So I tried to use Chrome. Received this error, however, Chrome is supposed to be supported:
Error - You have opened Nintex Forms Designer in an unsupported browser. Please close Nintex Forms Designer and reopen using one of our supported browsers as specified in the Nintex Forms installation guide, available for download from connect.nintex.com.
Same thing happens to me using IE version 11xx. What I do to get around it is, you have to Maximize the browser window and then Open the configuration windows. This will allow for all the tabs along the top to display correctly. I also use the zoom in and out function of the browser to help view things when they get hidden.
I do not think IE 10xxx suffers these same issues.
As for your Chrome comment, only IE is supported for design at this time. (Users can view forms using other browsers, but designers can only use IE).
I have also since found that running IE in Widows 8 (which maximises the screen) works.