to create appointment, just click the + button at the top (on the widget). or if you use the s planner apps, there's also a + and then you choose whether its an EVENT, TASK or MEMO. but it is a good idea to check the calendars you have (especially if you have a few Google accounts on the phone). That way, you know which color is for what. you can actually choose which calendar account to use when creating new item.

just start S PLANNER apps --> MENU (left button) --> CALENDARS. You'll see a list of calendars here (and the colours).

are you sure its 'APPOINTMENT'? could it be that its an EVENT... and customised with background/ icon?

update 1:
btw, wanna confirm... you are using note 2, right? and do you know your Android version? coz it looks like your calendar seems to be the old one... compared to what i have. i'm running stock rom, 4.3.


update 2:
i just played around with it. the yellow colour square means its a MEMO.

from S PLANNER, when i click +, i can select MEMO. but i'm on 4.3.

not sure about 4.1.2... sorry. maybe if you dun see it from widget, try from the apps?