Make fieldset layout icons optional

Change-Id: I7617a35bd9e8322d0b9f8e225885ccbe5fa230ee
Make references dialog scroll

If the content in the sub-editor gets big enough, this can be a problem.

Change-Id: Ic189011e64090186d87a397b2b047057a97f2a3d
Merge changes Ic189011e,I7617a35b

* changes:
  Make references dialog scroll
  Make fieldset layout icons optional