As usual, the solution to the bug is a simple work around. By using a set selection of a field in the portal, the same effect is had.
But this should not be necessary.
You mentioned "Ungroup" this could be significant. Objects on your layout can be named and then, when you group them, you can give the group a name. Go to object can still go to the individual named items, but you can no longer see the object names in the inspector until you ungroup the group and select one individual group member at a time. As long as the items are grouped, only the group's object name is visible and editable in the Inspector.
This can be especially tricky if you select a layout object and set it up as a button. Turning an object groups the selected object(s) with an invisible button object and this will, for the reasons I have just listed, hide the object names of any of the individual objects that you just turned into a button.