title: Plot is not reset
body: <p>i need your help. My program reads a M-File which is a recorded Video.
  To display each image i use "imagesc", because the image is saved as a 200x200 Matrix with normalized values ranging from 0 to 1.</p>
  
  <p>After reading each image i do some calculus. The Result should be displayed as an overlay to the image(one Point, and one Line). With the code below this works as expected for the first iteration of the loop.</p>
  
  <p>At all further iterations the image is redrawn(which is correct) but the Point and Line is not cleared.</p>
  
  <p>How can i achieve that the plots are cleared when a new image is displayed.
  I tried several variations with the "hold" command. But got no success.</p>
  
  <p>Additional question(not that important):
  Is it possible to exchange the "plot" commands below with "set"(especially for the Point)?</p>
  
  <p>My program consist of several more Axes Elements which i cut out to keep the example simple. This means my UI is very slow with "plot" commands so i tried to speed it up with "set".</p>
  
  <p>It works quite well, but I'm not sure if a simple Point can be displayed with "set".</p>
  
  <p>Thanks in advance.</p>
  
  <pre><code>function work()
    h_figure = figure('Name','MainFig');
    hImage.ax = axes('Units', 'Pixels','Position', [50 375 200 200]);
  
    imagesc('Parent',hImage.ax,'CData',zeros(200));
    hImage.axc = get(gca, 'Children');
  
    hProfileLeft.ax = axes('Position', [50 200 200 100]);
    hProfileLeft.pl = plot(hProfileLeft.ax, 1:200); 
  
    for(frame = obj.Startframe:obj.Endframe)
      imgIntens= obj.video.A.intens(:,:,frame);
      ProfileResult = doSomeCalc(someArgs); 
  
      set(hImage.axc, 'CData', imgIntens); % Show Image(200x200 double)
  
      hold(hImage.ax, 'on'); % Using hold so that plot is overlayed
  
      plot(ProfileResult.peaks.x, ProfileResult.peaks.y,'Parent',hImage.ax); % Simple Point
      plot(ProfileResult.corridor.left, 1:200, 'Parent',hImage.ax); % Line
  
      set(hProfileLeft.pl,'YData', ProfileResult.trace); % Draw data to different axes
      hold(hImage.ax, 'off');
    end
  
  end
  </code></pre>