# Quick Q for RemoveObserver
**URL:** https://discourse.slicer.org/t/quick-q-for-removeobserver/28354
**Category:** Support
**Tags:** python
**Created:** [March 13, 2023, 6:33pm UTC](https://discourse.slicer.org/t/quick-q-for-removeobserver/28354 "2023-03-13T18:33:13Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@aiden.zhu](https://discourse.slicer.org/u/aiden.zhu)
#### Post date: [March 13, 2023, 6:33pm UTC](https://discourse.slicer.org/t/quick-q-for-removeobserver/28354/1 "2023-03-13T18:33:13Z")
Hi all,
quick question about “RemoveObserver”==\>
After I did the following to add one observer
“”"
crosshairNode=slicer.util.getNode(“Crosshair”)
crosshairNode.AddObserver(slicer.vtkMRMLCrosshairNode.CursorPositionModifiedEvent, self.onMouseMoved)
“”"
I did try
crosshairNode.RemoveObserver(slicer.vtkMRMLCrosshairNode.CursorPositionModifiedEvent)
but no effect from this line.
how to remove the observer?
---
### Author:  [@smrolfe](https://discourse.slicer.org/u/smrolfe)
#### Post date: [March 13, 2023, 7:46pm UTC](https://discourse.slicer.org/t/quick-q-for-removeobserver/28354/2 "2023-03-13T19:46:44Z")
You can remove an observer using the tag generated when the observer was added. See the [this example](https://slicer.readthedocs.io/en/latest/developer_guide/script_repository.html#display-mouse-pointer-coordinates-in-alternative-coordinate-system) in the script repository.
---
### Author:  [@aiden.zhu](https://discourse.slicer.org/u/aiden.zhu)
#### Post date: [March 13, 2023, 8:08pm UTC](https://discourse.slicer.org/t/quick-q-for-removeobserver/28354/3 "2023-03-13T20:08:39Z")
Thanks a lot for the solution.
It worked after taking all parameters to the root “self”.