macOS OpenGL "Picking" error specific to Mac

    GLuint selectBuf[buffsize]; for(int p=0;p<buffsize;p++){selectBuf[p]=0;}
    GLint hits=0;
    GLint viewport[4]; // The Size Of The Viewport. [0] Is <x>, [1] Is <y>, [2] Is <length>, [3] Is <width>
    
    glSelectBuffer (buffsize, selectBuf); 
    glRenderMode(GL_SELECT); 
    glInitNames();
    
    ///////////////////////////////////////////////////////Problem exists between here and....!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
    glMatrixMode (GL_PROJECTION);
    glPushMatrix ();
    glLoadIdentity ();
    glGetIntegerv(GL_VIEWPORT, viewport);
    
    /* create 5x5 pixel picking region near cursor location */
    gluPickMatrix((GLdouble) xmouse, (GLdouble) (viewport[3] - ymouse), 3.0, 3.0, viewport);//(viewport[3] - ymouse) for Windows
    ///////////////////////////////////////////////////////////////////////////////////...here ????? !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
    gluPerspective(videocam.xwinmin, videocam.ywinmin, videocam.camnear, videocam.camfar);
    glMatrixMode(GL_MODELVIEW);
    
    cout<<"Buffer contents before picking: ";
    for(int i=0;i<buffsize;i++){cout<<selectBuf[i]<<", ";}

// moved from above
glPushName(0);
    
    draw();

// added to balance above
glPopName();
    
// match pushed above
glMatrixMode(GL_PROJECTION);

    glPopMatrix ();

glMatrixMode(GL_MODELVIEW);

    glFlush();
    picking=false;
    
    hits = glRenderMode(GL_RENDER);
    
    cout<<"\nValue of 'hits' immediately after glRendermode() is "<<hits<<endl;
    proces*****(hits, selectBuf);
    cout<<"DONE processing picks!!!!!!!!!!!!!!!!!!!!!!!\n"<<endl;

void Face::drawface(float color[4])
{
    int x = 2000;
    int y = x;

    if ( swapx == true ) { x *= (-1); }
    if ( swapy == true ) { y *= (-1); }

    for ( int j = -3+swapy; j < 3+swapy; j++ )
    {
        for ( int i = -3+swapx; i < 3+swapx; i++ )
        {
            glPushMatrix();

                glMaterialfv(GL_FRONT, GL_EMISSION, color);
                glTranslatef(i*(x), j*(y), 0.0f);///////proper 'z' value assigned in tiles.display(...); see squares.cpp
    
                // NOTE: Uncommented and added condtional output of namestack value
                glLoadName(tiles[(3+i-swapx)*6+(3+j-swapy)].getID());
                if ( picking ) std::cout << "glLoadName - " << tiles[(3+i-swapx)*6+(3+j-swapy)].getID() << std::endl;
    
                // NOTE: Uncommented and added condtional output of namestack value
                glPushName(tiles[(3+i-swapx)*6+(3+j-swapy)].getID());
                if ( picking ) std::cout << "glPushName - " << tiles[(3+i-swapx)*6+(3+j-swapy)].getID() << std::endl;
    
                    tiles[(3+i)*6+(3+j)].display((i+j+dark)%2);
    
                glPopName();

            glPopMatrix();
        }
    }
}

void buttons(GLint button, GLint action, GLint xmouse, GLint ymouse)
{   
    if ( (button==GLUT_LEFT_BUTTON)&&(action==GLUT_DOWN)&&leftbutton==false )
    {
        videocam.setXmouse(xmouse);
        videocam.setYmouse(ymouse);
        
        leftbutton=true;

        GLuint selectBuf[buffsize];
        glSelectBuffer (buffsize, selectBuf);   

        glRenderMode(GL_SELECT); 
        
        glMatrixMode (GL_PROJECTION);
        glPushMatrix ();
        glLoadIdentity ();

        GLint viewport[4];
        glGetIntegerv(GL_VIEWPORT, viewport);
        
        /* create 3x3 pixel picking region near cursor location */
        gluPickMatrix((GLdouble) xmouse, (GLdouble)(viewport[3] - ymouse), 3.0, 3.0, viewport);
        
        gluPerspective(videocam.xwinmin, videocam.ywinmin, videocam.camnear, videocam.camfar);
        glMatrixMode(GL_MODELVIEW);

        glInitNames();

        // NOTE:
        // make sure something is on the namestack or 'glLoadName' call in 'Face::drawface'
        // will generate an namestack underflow error

        glPushName(0);
                
        picking=true;
        draw();
        
        glMatrixMode (GL_PROJECTION);
        glPopMatrix ();
        picking=false;

        // NOTE:  'hits' is being return as -1
        
        GLint hits;
        hits = glRenderMode(GL_RENDER);
        if ( hits < 0 )
        {
            // NOTE:
            // If the overflow bit was set when glRenderMode was called, a negative hit record count is returned.
            // You'll need to increase the size of 'buffsize'
            // For me this went away between 256 and 512
            cout << "\nValue of 'hits' was negative!!!" << endl;
        }
        else if ( 0 == hits )
        {
            cout << "\nThere were no hits!!!" << endl;
        }
        else if ( hits > 0 )
        {
            cout << "\nValue of 'hits'  immediately after glRendermode() is " << hits << endl;

                proces*****(hits, selectBuf);

            cout << "DONE processing picks!!!!!!!!!!!!!!!!!!!!!!!\n"<<endl;
        }
    }
    
    if ( action == GLUT_UP && leftbutton == true )
    {
        leftbutton = false;
    }
}

    delete [] hitsets[1];
    delete [] hitsets[0];