I like the new Iteractive grid, and all it's functionality, very mutch! One thing I encounter is the following:
When I add a new interactive grid to a page and make it editable, somehow the width of the columns are wrong calculated and a scrollbar is shown. See this example:

It looks like the first two columns aren't taken in account when calculating the width. You can see the the above example at:https://apex.oracle.com/pls/apex/f?p=20983:2 . This page was generated using the wizard and 'enable editing' was put on - rest was all on default values.