Mosaic Custom doesn't pick up drawing sets correctly.

[led]

Describe the bug
When using the Mosaic Custom PFM, it's pretty much impossible to select different drawing sets when you have multiple masked areas as the Drawing Sets drop-down isn't populated correctly.

To Reproduce
Set up the 'Mosaic Custom' PFM. Add in a mask image and try to select different drawing sets for the different masked colours. For me, the drop-down with the Drawing Sets isn't correctly populated.

Expected behavior
To be able to select different drawing sets that have been created.

DrawingBotV3 Version
1.6.16 Stable

Operating System
Mac M2