In iNotes for 6.0.1 CF2 opening your mail in portal view (http://path-to-mailfile/iNotes/Mail/?OpenDocument&ui=portal) would open your mailfile and hide the panel on the left.
It seems that in 6.0.3 this has changed. The panel is just there by default. Is there a way to disable/hide the panel using a prameter in the url?