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Following these instructions you can set a categorized message's font color to be the same as the message's class color.
Click to enlarge
View tab
Select a folder in which you want to apply font color and select View Settings in the View tab.
Advanced View Settings
Click on Conditional Formatting...
Setting Conditional formatting
Click on Add.
Adding a rule
Give a descriptive name for the fule and click on Font...
Selecting font color
Select font color from the drop-down menu and click on OK.
Setting condition
Click on Condition...
Categories
click on Categories... on the More Choices tab.
Selecting a color category
Select a category to choose its font color. Click on OK.
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