STR:

Go to your decks
Create a new deck ( I was working on Artisan Brawl)
Select a commander in blue/black (I used Rona)

Type the following search string:
-o:"discard" o:"draw two"
Result: you get many cards, as expected.

Now change the search string to:

o:"draw two" -o:"discard"

Expected Result: Same set of cards shown

Actual result: Text search goes red, won't search.