JOGL GL_SELECT picking fails - opengl

Question

I am using the GL_SELECT method to achieve mouse selection in OpenGL using JOGL Java Library.
I know the method is deprecated and such, but it is a simple school assignment and this should do it.
However I am having some trouble: even though something is rendered in GL_SELECT mode, glRenderMode(GL_RENDER) returns zero hits. The problem is deterministic, but I don't see a kind of pattern; for example, if I have a sphere in the center, it works if I click on its upper part, but not on its lower part. For a cube, it only won't work on one specific face. For a rectangle it works alright.
I have tested commenting out the glRenderMode(GL_SELECT) to check if something was indeed being rendered and yes, I could see the shape, but even so glRenderMode(GL_RENDER) gave me zero.
EDIT: I have also tested removing the call to gluPickMatrix() and the glRenderMode(GL_SELECT), which gave me exactly the same as the normal (non-picking) render, so the projection and model view matrixes are set up correctly I think.
So, I don't think I am rendering incorrectly in select mode. What can be going on?
EDIT: maybe this could be a hardware problem, as the method is deprecated. Is that possible?
Thanks in advance.
// Get required information
point.y = getHeight() - point.y;
gl.glGetIntegerv(GL2.GL_VIEWPORT, view, 0);
// Setup OpenGL for selection
gl.glSelectBuffer(64, buffer);
gl.glRenderMode(GL2.GL_SELECT);
gl.glInitNames();
// Setup projection matrix
gl.glMatrixMode(GL2.GL_PROJECTION);
gl.glPushMatrix();
gl.glLoadIdentity();
Util.glu.gluPickMatrix( point.x, point.y, 5.0, 5.0, view, 0 );
Util.glu.gluPerspective(camera.getFieldOfView(), getWidth() * 1.0 / getHeight(),
camera.getCloseDistance(), camera.getFarDistance() );
// Setup model view matrix for rendering
gl.glMatrixMode(GL2.GL_MODELVIEW);
camera.setView(gl); // Set to model view and use glLookAt
gl.glClear( GL2.GL_COLOR_BUFFER_BIT | GL2.GL_DEPTH_BUFFER_BIT );
// Render objects
for(int i = 0; i < shapeList.size(); i++) {
gl.glPushName(i);
// Execute transformations for translation/rotation/scale and render shape
shapeList.get(i).display(gl, false);
gl.glPopName();
}
// Process hits
hits = gl.glRenderMode(GL2.GL_RENDER);
System.out.println("Hits = " + hits);
// ... Process hits here ...
// Reset matrixes
gl.glMatrixMode(GL2.GL_PROJECTION);
gl.glPopMatrix();
gl.glMatrixMode(GL2.GL_MODELVIEW);
gl.glLoadIdentity();
camera.setView function:
public void setView( GL2 gl ) {
gl.glMatrixMode(GL2.GL_MODELVIEW);
gl.glLoadIdentity();
Util.glu.gluLookAt( eye[Axis.X], eye[Axis.Y], eye[Axis.Z],
target[Axis.X], target[Axis.Y], target[Axis.Z],
up[Axis.X], up[Axis.Y], up[Axis.Z] );
}