ID 334904 - Pinned/docked Curve Editors become orphaned as soon as the user dismisses the parent widget

Problem summary

Pinned/docked Curve Editors become orphaned as soon as the user dismisses the parent widget.
This means that as soon as the user selects a different layer or closes the node's properties, editing the Curve Editor no longer affects the node/layer that it was originally created from. Not even if the user reselects that layer or opens that node's properties.

Steps to reproduce

There are many ways to reproduce this, both with nodes and layers. Here's an example:

1. Launch Mari and open a Project.
2. Create and view a node with image data, such as a Cloud node.
3. Create a Brightness Lookup node and connect it to the Cloud node.
4. Open the Node Properties of the Brightness Lookup node and open the Curve Editor through the button.
   

   

5. Pin or dock the Curve Editor.
6. Edit the Curve so that you see a difference in your asset.
7. Close the node properties of the Brightness Lookup node.
8. Edit the Curve again.

Expected behaviour

Either:

1. Curve editor should remain bound to the property it controls, so that it still affects the shader.
2. Closing the node properties should dismiss any pinned/docked child widgets.

Actual behaviour

Curve editor remains open but it has no effect on the shader, as it is no longer linked to the property it was created from.

Workaround

Unknown.

Reproduced by support
This bug has been reproduced in:

Mari 6.0v2 - Windows 10 - CentOS7

Mari 4.2v1 - Windows 10 - CentOS7

Earliest version tested

Mari 4.2v1 - This issue appears to be in all tested versions of the product