ID 506647 - Unable to use .mtt custom Channel Preset Template files

Problem summary
Unable to use .mtt custom Channel Preset Template files
 
Customer reported version
Mari 4.8v2
 
Customer reported platform
n/a
 
Steps to reproduce
 
1) Download the attached TestTemplate.mtt file

2) Place the TestTemplate.mtt file in your .mari\TheFoundry folder (On Windows) or .config/TheFoundry folder (On Linux)

3) Launch Mari and open any project
 
4) Open the Channel Presets dialog (Channels > Channel Presets)
 
5) Attempt to select the TestTemplate template in the Template dropdown menu
 
Expected behaviour
The dropdown menu should open and the Template should be listed and selectable.
 
Actual behaviour
Clicking the Template dropdown has no effect.
 
Workaround
Unknown.
 
Reproduced by support
This bug has been reproduced in:
Mari 5.0v2 - Windows 10 - CentOS 7.9
Mari 4.8v2 - Windows 10