Outlook Office 365 Win 10 how do I control background colors of events?


Outlook version
Outlook 2019 64-bit
Email Account
I have Outlook 365 (Windows 10 home) and use the Calendar (as well as email) quite often to keep track of upcoming appoints. I don't understand the small vertical rectangular box immediately to the left of the event. If I set the category to Red (Important) which I added, the event is red, but the rest of the box is blank/white.

My Color setting is "Light Blue"
But sometimes the "vertical Box" is colored in and sometimes it is the category color (orange or yellow etc.). How do I control this?

Also sometimes the rest of the date box is blank (white) and sometimes it is shaded to match the category. Why? How do I control this?

As you can imagine, viewing this on the screen looks ok, but some colors look bold, dark, etc. on a color inkjet or b/w printer. Any idea of what is going on?

Thanks! (notice some of the colors and vertical box fill-ins on the attached screen shot.


Diane Poremsky

Senior Member
Outlook version
Outlook 2016 32 bit
Email Account
Office 365 Exchange
The little vertical box is the Show time as box - free, busy, out of office etc.

When you have an all day event marked busy, the entire day is shaded. If its assigned a category, its shaded the category color. If its a timed appt, only the event is colored.