private void showSolutionButton_Click( object sender, EventArgs e )
{
// check if learning algorithm was run before
if ( ( qLearning == null ) && ( sarsa == null ) )
return;
// disable all settings controls except "Stop" button
EnableControls( false );
// run worker thread
needToStop = false;
workerThread = new Thread( new ThreadStart( ShowSolutionThread ) );
workerThread.Start( );
}