When using Qt 5's QOpenGLWidget (a replacement for QGLWidget), flashing and...

When using Qt 5's QOpenGLWidget (a replacement for QGLWidget), flashing and transparent/strange graphics were seen after an identification operation and in particular, after annotation identification.  Identification is performed by encoding color information into the OpenGL color buffer.  Apparently, this color information remains displayed after an identification operation.  Now, after an identification operation is performed, a call is made to QOpenGLWidget::repaint() to redraw the graphics region.  This seems to update the frame buffer into which QOpenGLWidget draws into and thus corrects the problem with strange looking graphics after an identification operation.