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diff --git a/src/silx/gui/plot3d/scene/event.py b/src/silx/gui/plot3d/scene/event.py
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+++ b/src/silx/gui/plot3d/scene/event.py
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+# coding: utf-8
+# /*##########################################################################
+#
+# Copyright (c) 2015-2017 European Synchrotron Radiation Facility
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+# THE SOFTWARE.
+#
+# ###########################################################################*/
+"""This module provides a simple generic notification system."""
+
+from __future__ import absolute_import, division, unicode_literals
+
+__authors__ = ["T. Vincent"]
+__license__ = "MIT"
+__date__ = "17/07/2018"
+
+
+import logging
+
+from silx.utils.weakref import WeakList
+
+_logger = logging.getLogger(__name__)
+
+
+# Notifier ####################################################################
+
+class Notifier(object):
+    """Base class for object with notification mechanism."""
+
+    def __init__(self):
+        self._listeners = WeakList()
+
+    def addListener(self, listener):
+        """Register a listener.
+
+        Adding an already registered listener has no effect.
+
+        :param callable listener: The function or method to register.
+        """
+        if listener not in self._listeners:
+            self._listeners.append(listener)
+        else:
+            _logger.warning('Ignoring addition of an already registered listener')
+
+    def removeListener(self, listener):
+        """Remove a previously registered listener.
+
+        :param callable listener: The function or method to unregister.
+        """
+        try:
+            self._listeners.remove(listener)
+        except ValueError:
+            _logger.warning('Trying to remove a listener that is not registered')
+
+    def notify(self, *args, **kwargs):
+        """Notify all registered listeners with the given parameters.
+
+        Listeners are called directly in this method.
+        Listeners are called in the order they were registered.
+        """
+        for listener in self._listeners:
+            listener(self, *args, **kwargs)
+
+
+def notifyProperty(attrName, copy=False, converter=None, doc=None):
+    """Create a property that adds notification to an attribute.
+
+    :param str attrName: The name of the attribute to wrap.
+    :param bool copy: Whether to return a copy of the attribute
+                      or not (the default).
+    :param converter: Function converting input value to appropriate type
+                      This function takes a single argument and return the
+                      converted value.
+                      It can be used to perform some asserts.
+    :param str doc: The docstring of the property
+    :return: A property with getter and setter
+    """
+    if copy:
+        def getter(self):
+            return getattr(self, attrName).copy()
+    else:
+        def getter(self):
+            return getattr(self, attrName)
+
+    if converter is None:
+        def setter(self, value):
+            if getattr(self, attrName) != value:
+                setattr(self, attrName, value)
+                self.notify()
+
+    else:
+        def setter(self, value):
+            value = converter(value)
+            if getattr(self, attrName) != value:
+                setattr(self, attrName, value)
+                self.notify()
+
+    return property(getter, setter, doc=doc)
+
+
+class HookList(list):
+    """List with hooks before and after modification."""
+
+    def __init__(self, iterable):
+        super(HookList, self).__init__(iterable)
+
+        self._listWasChangedHook('__init__', iterable)
+
+    def _listWillChangeHook(self, methodName, *args, **kwargs):
+        """To override. Called before modifying the list.
+
+        This method is called with the name of the method called to
+        modify the list and its parameters.
+        """
+        pass
+
+    def _listWasChangedHook(self, methodName, *args, **kwargs):
+        """To override. Called after modifying the list.
+
+        This method is called with the name of the method called to
+        modify the list and its parameters.
+        """
+        pass
+
+    # Wrapping methods that modify the list
+
+    def _wrapper(self, methodName, *args, **kwargs):
+        """Generic wrapper of list methods calling the hooks."""
+        self._listWillChangeHook(methodName, *args, **kwargs)
+        result = getattr(super(HookList, self),
+                         methodName)(*args, **kwargs)
+        self._listWasChangedHook(methodName, *args, **kwargs)
+        return result
+
+    # Add methods
+
+    def __iadd__(self, *args, **kwargs):
+        return self._wrapper('__iadd__', *args, **kwargs)
+
+    def __imul__(self, *args, **kwargs):
+        return self._wrapper('__imul__', *args, **kwargs)
+
+    def append(self, *args, **kwargs):
+        return self._wrapper('append', *args, **kwargs)
+
+    def extend(self, *args, **kwargs):
+        return self._wrapper('extend', *args, **kwargs)
+
+    def insert(self, *args, **kwargs):
+        return self._wrapper('insert', *args, **kwargs)
+
+    # Remove methods
+
+    def __delitem__(self, *args, **kwargs):
+        return self._wrapper('__delitem__', *args, **kwargs)
+
+    def __delslice__(self, *args, **kwargs):
+        return self._wrapper('__delslice__', *args, **kwargs)
+
+    def remove(self, *args, **kwargs):
+        return self._wrapper('remove', *args, **kwargs)
+
+    def pop(self, *args, **kwargs):
+        return self._wrapper('pop', *args, **kwargs)
+
+    # Set methods
+
+    def __setitem__(self, *args, **kwargs):
+        return self._wrapper('__setitem__', *args, **kwargs)
+
+    def __setslice__(self, *args, **kwargs):
+        return self._wrapper('__setslice__', *args, **kwargs)
+
+    # In place methods
+
+    def sort(self, *args, **kwargs):
+        return self._wrapper('sort', *args, **kwargs)
+
+    def reverse(self, *args, **kwargs):
+        return self._wrapper('reverse', *args, **kwargs)
+
+
+class NotifierList(HookList, Notifier):
+    """List of Notifiers with notification mechanism.
+
+    This class registers itself as a listener of the list items.
+
+    The default listener method forward notification from list items
+    to the listeners of the list.
+    """
+
+    def __init__(self, iterable=()):
+        Notifier.__init__(self)
+        HookList.__init__(self, iterable)
+
+    def _listWillChangeHook(self, methodName, *args, **kwargs):
+        for item in self:
+            item.removeListener(self._notified)
+
+    def _listWasChangedHook(self, methodName, *args, **kwargs):
+        for item in self:
+            item.addListener(self._notified)
+        self.notify()
+
+    def _notified(self, source, *args, **kwargs):
+        """Default listener forwarding list item changes to its listeners."""
+        # Avoid infinite recursion if the list is listening itself
+        if source is not self:
+            self.notify(*args, **kwargs)