title: Matlab: Selected data (through brushing) in GUI plot is not being stored
body: <p>I am plotting these two curves on an axes:</p>
  
  <pre><code>LH(1) = copyobj(T2pb1hLine(2), S.T2pb1Ax(2)); 
  LH(2) = copyobj(T2pb1hLine(2), S.T2pb1Ax(2)); 
  set(LH(1), 'XData', PressNoOutliers, 'YData', zNoOutliers, 'linestyle',...
              'x', 'Color', 'm');
  set(LH(2), 'XData', PressNoOutliers2, 'YData', zNoOutliers2, 'linestyle',...
              's', 'Color', 'b');
  </code></pre>
  
  <p>Then I am using this callback function to brush the data and store it:</p>
  
  <pre><code>brush on
  pause
  hBrushLine = findall(S.T2pb1Ax(2), 'tag', 'Brushing');
  brushedData = get(hBrushLine, {'Xdata', 'Ydata'});
  brushedIdx = ~isnan(brushedData{1});
  PSel = brushedData{1}(brushedIdx);
  zSel = brushedData{2}(brushedIdx);
  </code></pre>
  
  <p>I am able to brush the data, however, the data is not being stored which results in empty vectors for <code>PSel</code> and <code>zSel</code>. Apparently, if I were not using <code>copyobj</code> and plotting only single curve then I am able to get the data by brushing for <code>PSel</code> and <code>zSel</code>. Any guesses what can I do to store the data while I am using <code>copyobj</code> to plot the 2 curves together? </p>