Well, optically, 3dsmax would fit in there quite nicely… (The same with Audition as sound editor).
It would allow me to group together with some UE4 controls in one tabbed panel.
Instead of switching tasks it would be just clicking over to another tab.
It would give me the same flexibility as with other UE4 panels.
Imagine 3dsmax in the middle, sourrounded by UE4 panels. A bit difficult to achieve if its an external window…
Cheers,