Would you like to search what your opponent might play (in other words, show suggestions based on your opponents rack...); if so this would not be possible as the Wordfeud does not show the opponents rack.
If you would like to see the suggestions based on your rack while you are not on turn, this would be possible but is not really useful (as the board might probably change).
Option 2: I would like to see the suggestions based on my rack while it's not my turn. At the moment this is possible when you do not refresh the WF list after you completed your turn.
Sure, the board will change, but you can try some suggestions.