title: Hover issue in PyQt
body: <p>I want to do hover. I saw an example and then write a script which will be use as I made program. I am facing one problem that hover only occur if you put mouse on the left corner of button. I want that it will happen for all the button that if i move cursor on button then it should change.</p>
  
  <p>Here is my code:</p>
  
  <pre><code>from PyQt4 import QtGui, QtCore
  from PyQt4.QtCore import pyqtSignal
  import os,sys
  
  class HoverButton(QtGui.QToolButton):
      def enterEvent(self,event):
          print("Enter")
          button.setStyleSheet("background-color:#45b545;")
  
      def leaveEvent(self,event):
          button.setStyleSheet("background-color:yellow;")
          print("Leave")
  
  app = QtGui.QApplication(sys.argv)
  widget = QtGui.QWidget()
  button = QtGui.QToolButton(widget)
  button.setMouseTracking(True)
  buttonss =  HoverButton(button)
  button.setIconSize(QtCore.QSize(200,200))
  widget.show()
  sys.exit(app.exec_())
  </code></pre>