How does Applied Entropy (Control) and Sealed Scroll interact?
No, the player can not target the sealed scroll.

The rules (emphasis from the printed rules) for fast actions State :- 


  You may not use a Fast Action after you take your regular
  Action.  Also, you may not use a Fast Action in place of a Regular
  Action.


The Control spell, level 3 of Applied Entropy, says :-


  Action: use an opponents Treasure Card, exhausting it after use.


Sealed Scroll says :-


  Fast Action: Research a Legendary Spell of your choice, then place this into your personal discard pile.


So as the player is in his action phase he can not then go back and do anything that counts as a Fast Action from his own cards or that of another players.  As Control is 'Action' and Sealed Scroll is 'Fast Action' this is completely prevented.