I use message-marking in kmail for accounting bills.
I basically use 3 unique categories (i use this term for the different markings):
"unpaid" (setting the background-color to YELLOW)
"paid" (bg set to GREEN)
"reminded" (bg set to RED)
And one general "Mastercategory" named "# Buchhaltung" (german for accounting) where this category doesnt define any colors at all.
But there is no way to use them in any cumulative way .. like:
an accounting-related mail may be only one of the color-categories (red/green/yellow) but it is always member of the (colorless) accounting-category.
But only one of them (first by sort order) is taking effect while others are ignored/overruled.
STEPS TO REPRODUCE
1. mark an email as "accounting"(colorless)
2. mark the same email as "RED"
marked mail stays in the default colorscheme as if not marked at all
since only one of the markings actively sets a backgroundcolor , i would expect it to be RED .. but is stay colorless albeit that category doesnot force any backgroundcolor at all.
Workaround for me now is: I moved the colorless-category after the colored-categories .. to avoid this affect .. not sure how it is really planned, but i wouldnt expect settings to be ignored like this.
KDE Frameworks 5.55.0
Qt 5.9.7 (kompiliert gegen 5.9.7)
thanks for looking into this