It is hard to tell, if an object belongs to a portal/panel or is floating on to of it. Especially if I drag the object I like to have a visual mark telling me, now it is part of the portal/panel, now it is not.
If I could even could control this when I drag the object, that would be awesome. It should work even if the object is larger than the visible part of the portal/panel. Perhaps the up/down keys could work. When I drag the object and press the down key, the object will connect with the portal/panel, if I press the up key, it will detach itself. Or, when I use arrow keys to move an object, pressing the shift key should not change the connection to portal/panel.
This feature would be very helpful for developers. Too often a single use of an arrow key detached an object from the portal and requires fiddly work with the object, making it smaller, dragging it inside the portal and resizing it again.