The top plate the cup sits in is not glued, it clips in and is removable. If water is seeping out here there are a few possibilities. The whistle is related, water is being sucked into the air intake for the same reason, the water level inside the skimmer is too high. A slow trickle here is not unusual, it can happen when a skimmer has been thoroughly cleaned and the pump is at its optimum.
1) The blue sponge on the stand pipe is above the top of the pipe, it should always be flush or below the top of the pipe.
2) The pipe is not fully inserted in the elbow or the elbow is pushed too far into the body.
3) The skimmer is submerged too deep.
4) The skimmer is unlevel.
5) Again, it could be normal, if you cleaned it recently, especially the pump, and it is just a very slow intermittent trickle, that is fine and will go away.