instead of using loop() and noLoop() you could do something like this:

1. boolean is_looping = false;
2. void setup(){
3. }
4. void draw(){
5.   if(!is_looping)
6.     return;
7.    
8.   println(frameRate);
9. }
10. public void mouseReleased(){
11.   is_looping = false;
12. }
13. public void mousePressed(){
14.    is_looping = true;
15. }

or, even shorter:

1. void setup(){
2. }
3. void draw(){
4.   if(!mousePressed)
5.     return;
6.   println(frameRate);
7. }

In Processing the main thread performs event handling as well as redrawing the sketch. When noLoop() is called it not onlt stops redraws but also stops your sketch responding to mouse and keyboard events. The GUI libraries such as Control5P and G4P hook into this thread so noLoop will stop them from working.

The soultion I have found useful with G4P is to use frameRate -  when the mouse is released use frameRate(5) to reduce the frame rate to 5 frames per second then when the mouse is pressed increase the frameRate to at least 60fps which will should enable Control5P to do its stuff. You can try experimenting with the framerates to get what you want.