Commit
fc39665affd0b2f94cdbad59991398cdc14e8cff
by alex.orzechowskiChanged to support compatibility.
This change was made to buildcraft would work better when a IInventory returned false when calling func_102007_a function. Now continues to check other slots. (Maybe you're using func_102007_a to return true if you want items to only go into a specific slot and not out.)
(commit: fc39665)