if it persists on a specific computer try update graphic card driver?
and check again.
some info might see by adding
void mysysinfo() {
println( "System : " + System.getProperty("os.name") + " " + System.getProperty("os.version") + " " + System.getProperty("os.arch") );
println( "JAVA : " + System.getProperty("java.home") + " rev: " +javaVersionName);
//println( "\n" + isGL() + "\n" );
println("OPENGL_VENDOR: " + PGraphicsOpenGL.OPENGL_VENDOR+" OPENGL_RENDERER: " + PGraphicsOpenGL.OPENGL_RENDERER+" OPENGL_VERSION: " + PGraphicsOpenGL.OPENGL_VERSION+" GLSL_VERSION: " + PGraphicsOpenGL.GLSL_VERSION);
println( "user.home : " + System.getProperty("user.home") );
println( "user.dir : " + System.getProperty("user.dir") );
println( "sketchPath : " + sketchPath() );
println( "dataPath : " + dataPath("") );
println( "dataFile : " + dataFile("") );
}
void keyPressed() {
if ( key == 'i' ) mysysinfo();
}