This might help
import g4p_controls.*;
GCustomSlider slider;
public void setup(){
size(480, 320, JAVA2D);
createGUI();
customGUI();
}
public void draw(){
background(230);
}
public void customGUI(){
// You will have to experiment with the 2nd and 3th parameters to get
// the relative position for the tooltip.
// Since the slider has been rotated 90 degrees the 2nd parameter affects
// the vertical position and the 3rd parameter the horizontal position
slider.setTip("Pick a number", -40, -50);
slider.setTipHorz(true);
}
// Create all the slider control
public void createGUI(){
G4P.messagesEnabled(false);
surface.setTitle("Sketch Window");
slider = new GCustomSlider(this, 200, 40, 230, 50, "grey_blue");
slider.setRotation(PI/2, GControlMode.CORNER);
slider.setLimits(0.5, 0.0, 1.0);
slider.setNbrTicks(10);
slider.setNumberFormat(G4P.DECIMAL, 2);
slider.setOpaque(false);
}