Agenda items staying the default colours until reselect the agenda

So recently i have been having some outlook problems nothing big but mighty annoying
When i start outlook and then go to my agenda all my agenda items show green (the default colour for any unassigned category) but when I turn of this agenda of and reselect it then and only then starts showing the assigned colours
The things i have done so far is a complete reinstall of outlook, complete deinstall of all the office application, cleared the cache locations, new outlook profile. if anyone has an idea on how to fix this, i would be pleased to hear it. Thank you in advance

( i the agenda items)