ID 327854 - Mari 4 does not retain custom layouts

Problem summary
Mari 4 does not retain custom layouts

Customer reported version
4.0v1

Customer reported platform
centos7

Steps to reproduce

1) Create a custom layout/palette. Navigate to Views > Palettes > Lights

2) Repeat the above steps but select a different palette. ie, Views > Palettes > Modo Render

3) Drag one of the floating windows onto the other, creating a custom palette.

4) Save the layout. Navigate to Views > Save Layout > save your layout

5) Close and then relaunch Mari
Result: Mari will not load previous layout by default

6) Navigate to Views > Load Layout > Select custom layout
Result: Mari will not load previously saved custom layout

Workaround
n/a

Reproduced by support
Reproduced:
Mari 4.0v1 - CentOS 7 - Win 10

Unable to reproduce:
Mari 3.3v1

Earliest version tested
Mari 3.3v1 - works as intended

Expected behaviour
Mari would remember previous layout used. 
Mari would load custom layout

Actual behaviour
4.0v1 does not remember nor load custom layouts