ID 381814 - Creating a custom palette window results in an incorrect Layer header when switching between channels.

Problem summary
Creating a custom palette window results in an incorrect Layer header when switching between channels.

Customer reported version

4.2v2

Customer reported platform

Steps to reproduce

1) Open Mari and the Example Project 

2) Create a custom palette window with the Layers Palette and the Channels Palette

3) Switch between the channels

Result: The Layers Palette header is not updating accordingly to the selected channel

Workaround
Unknown. 

Reproduced by support
This bug has been reproduced in:

Mari 4.2v2 - Windows 10 - CentOS 6.9

Mari 4.1v1 - Windows 10 

Mari 4.0v4 - Windows 10 

Earliest version tested

4.0v4 - This feature did not exist before this version
​

Expected behaviour

The Layer Palette header to represent the selected channel regardless of the Custom Palette window

Actual behaviour
The header does not update correctly