i resized the kickoff menu when i started using this kde install

i click the kickoff now and it opened in its default size

i resized it back and closed it

i opened it again and moved my mouse to 'applications'

the screen resolution changed from 1680x1050 to 1024x768




kickoff remained open and functional

it looks like a one-off and i can't make this error happen again

i alt ctrl F1'd to the console and saw this (i dont know in which log to find it)

You can find that information in ~/.xsession-errors usually.

and to what i assign it if i report bug ?

I would report it aganist Plasma. Please ensure you are not using KRandRTray, which could be doing this instead.

in fact krandrtray opened up the next time i started kde

so its kickoff started krandrtray for some reason and krandrtay changed the resolution ?

Kickoff didn't start KRandRTray. I do not know why KRandRTray was started, but it was the one that changed your desktop resolution.