#326 Exception in taurustrend2d (signal disconnection)

[Carlos Pascual]

To reproduce, just launch taurustrend2d --demo

cpascual@pc218:~$ taurustrend2d --demo 
MainThread     INFO     2016-07-18 17:47:11,578 TaurusRootLogger: Using "PyQt4" for Qt
MainThread     INFO     2016-07-18 17:47:11,684 taurus.qt.qtgui.icon.icon: Setting Tango icon theme (from /tmp/kkt4/usr/local/lib/python2.7/dist-packages/taurus/qt/qtgui/icon/)
Traceback (most recent call last):
  File "/tmp/kkt4/usr/local/lib/python2.7/dist-packages/taurus/qt/qtgui/extra_guiqwt/tools.py", line 264, in items_changed
    self.activate_command(plot, self.action.isChecked())
  File "/tmp/kkt4/usr/local/lib/python2.7/dist-packages/taurus/qt/qtgui/extra_guiqwt/tools.py", line 247, in activate_command
    item.scrollRequested.disconnect(self.onScrollRequested)
TypeError: 'instancemethod' object is not connected