Not a big issue, just wanted ti let you know.
When opening PM with the preference “Restore Contact Sheets from last session” enabled, and deselected a color class, the images with the color class is displayed. Toggling the color Classon and then off correctly hides the images with the color class.
I use custom color class names.
Photo Mechanic Version 6.0, build 3291 (fd6a2a2)
macOS Mojave Version 10.14.5
Rgds
Michael