Traceback (most recent call last):  File "\lib\site-packages\matplotlib\cbook\__init__.py", line 270, in process    func(*args, **kwargs)  File "\lib\site-packages\matplotlib\backend_bases.py", line 3074, in _zoom_pan_handler    self.release_pan(event)  File "\lib\site-packages\matplotlib\backend_bases.py", line 3147, in release_pan    ax.end_pan()  File "\lib\site-packages\matplotlib\axes\_base.py", line 4239, in end_pan    del self._pan_startAttributeError: _pan_start

importsysimportosfromPyQt5.QtCoreimportQtfromPyQt5.QtWidgetsimportQAbstractItemView,QAction,QApplication,QFileDialog,QInputDialogfromPyQt5.uicimportloadUiTypefrommatplotlib.figureimportFigurefrommatplotlib.backends.backend_qt5aggimport (FigureCanvasQTAggasFigureCanvas,NavigationToolbar2QTasNavigationToolbar)Ui_MainWindow,QMainWindow=loadUiType('window.ui')classMain(QMainWindow,Ui_MainWindow):def__init__(self, ):super(Main,self).__init__()self.setupUi(self)self.fig_dict= {}self.figdata_dict= {}self.mplfigs.itemClicked.connect(self.changefig)fig=Figure()self.addmpl(fig)defchangefig(self,item):text=item.text()text=str(text)self.rmmpl()self.addmpl(self.fig_dict[text])defaddfig(self,name,fig):self.fig_dict[name]=figself.mplfigs.addItem(name)defaddmpl(self,fig):self.canvas=FigureCanvas(fig)self.mplvl.addWidget(self.canvas)self.canvas.draw()self.toolbar=NavigationToolbar(self.canvas,self.mplwindow,coordinates=2)self.toolbar.zoom()self.mplvl.addWidget(self.toolbar)defrmmpl(self,):self.mplvl.removeWidget(self.canvas)self.canvas.close()self.mplvl.removeWidget(self.toolbar)self.toolbar.close()if__name__=='__main__':fig1=Figure()ax1f1=fig1.add_subplot(111)ax1f1.plot([1,2,3,1,2,3])fig2=Figure()ax1f2=fig2.add_subplot(111)ax1f2.plot([100,200,300,400,100,200,300])ax1f2.plot([200,300,400,200,300,400])app=QApplication(sys.argv)main=Main()main.addfig('Oneplot',fig1)main.addfig('Twoplots',fig2)main.show()sys.exit(app.exec_())

<?xml version="1.0" encoding="UTF-8"?><ui version="4.0"> <class>MainWindow</class> <widget name="MainWindow">  <property name="geometry">   <rect>    <x>0</x>    <y>0</y>    <width>1280</width>    <height>768</height>   </rect>  </property>  <property name="windowTitle">   <string>MainWindow</string>  </property>  <widget name="centralwidget">   <layout name="horizontalLayout">    <item>     <widget name="mplwindow" native="true">      <property name="sizePolicy">       <sizepolicy hsizetype="Expanding" vsizetype="Preferred">        <horstretch>0</horstretch>        <verstretch>0</verstretch>       </sizepolicy>      </property>      <property name="mouseTracking">       <bool>false</bool>      </property>      <property name="focusPolicy">       <enum>Qt::ClickFocus</enum>      </property>      <layout name="mplvl"/>     </widget>    </item>    <item>     <widget name="mplfigs">      <property name="sizePolicy">       <sizepolicy hsizetype="Fixed" vsizetype="Expanding">        <horstretch>0</horstretch>        <verstretch>0</verstretch>       </sizepolicy>      </property>      <property name="minimumSize">       <size>        <width>200</width>        <height>0</height>       </size>      </property>      <property name="maximumSize">       <size>        <width>200</width>        <height>16777215</height>       </size>      </property>      <property name="focusPolicy">       <enum>Qt::NoFocus</enum>      </property>     </widget>    </item>   </layout>  </widget>  <widget name="menubar">   <property name="geometry">    <rect>     <x>0</x>     <y>0</y>     <width>1280</width>     <height>21</height>    </rect>   </property>  </widget>  <widget name="statusbar"/> </widget> <resources/> <connections/></ui>