As far as I know here are the places where the sidebar color can be customized:
1) Inside of the task property pane:
If it's not visible, press Alt+ F2 or go to Menu View > Task Parameters > Format.
Find there the Format group.
Click More > Highlight tab > Side Bar color
2) Automatic formatting
Tools > Options > Automatic Formatting
3) Themes
Tools > Options > Themes and formatting
Best regards
Andrew
среда, 5 августа 2020 г. в 17:24:22 UTC+3, arnyeinstein: