title: pyqtgraph: How to link two PlotWidget windows to show the same plot?
body: <p>I am developing an orbital analysis tool using PyQT5 and pyqtgraph!</p>
  
  <p>See: <a href="https://github.com/3fon3fonov/trifon" rel="nofollow noreferrer">https://github.com/3fon3fonov/trifon</a></p>
  
  <p>My tool has a plotting area with ~15 plots shown in different tab windows, which show different aspects of the data analysis.</p>
  
  <p>The tool it self is assembled with the Designer-qt5, while the QGraphicView widgets are promoted to pyqtgraphs's PlotWidgets</p>
  
  <p>For example in the gui.py I initialize the plots like this:</p>
  
  <pre><code>def initialize_plots(self):
      global p1,p2,p3,p4,p5,p6,p7,p8,p9,p10,p11,p12,p13,p14,p15,pe
      p1  = self.graphicsView_timeseries_RV
      p2  = self.graphicsView_timeseries_RV_o_c
      p3  = self.graphicsView_timeseries_phot
      p4  = self.graphicsView_timeseries_phot_o_c
      p5  = self.graphicsView_timeseries_activity
      p6  = self.graphicsView_timeseries_correlations
      # ...
      pe  = self.graphicsView_extra_plot
      # ...
  </code></pre>
  
  <p>so p1-p6 in this case are different PlotWidget objects on which I add Items/Plot data, i.e.  p1.plot(x,y), p1.addItem(), etc.</p>
  
  <p>What I want is to link pe to any of p1-p6!. pe is an extra plot so the user can choose from those already available/created.
  Thus the user can select which plot he/she wants to see next to the main plot.</p>
  
  <p>Lets imagine that the  ComboBox dropdown menu selects between p1-p6 objects, so</p>
  
  <p><code>pe = p1</code>, or later: <code>pe = p4</code></p>
  
  <p>for example.</p>
  
  <p>Is there any way this to be done with PyQtgraph?</p>
  
  <p>I really tried all kind things in the last two weeks and nothing seems to work.</p>
  
  <p>I am aware of the</p>
  
  <pre><code>pe.setXLink(p1)
  pe.setYLink(p2)
  </code></pre>
  
  <p>but this only links the axes not the plot object itself. It doesn't work for me.</p>