I use ToDo Agenda 3.1.7-560. In the Settings under Calendar I see my calendars and my several opentasks-Tasklists. Before each calendar there is a coloured square and befor each task list there is a coloured tick.
When I scroll that window the squared colors do not change, but the colours of the ticks change to the colour of one task list. The list always shows all tasks of being in tge same colour, but in fact tge different task lists have different colours.