I am interested how to remove some icons from K2 Quick icons (admin) ?
Can anyone explain me?

Hi,

i've deleted the parts in the php-file, i don't wanna use.

Regards

You can do this with some css as well.
Although you will need to reapply the patch when you update K2.
In /administrator/modules/mod_k2_quickicons/tmpl/css/style.css

You can use the :nth-child(x) value to hide an icon.

eg:
Although overriding the module and removing the links as Franz suggested is a preferable solution.

@Krikor

Thank you for your (better) Solution. I'll use ist.

Regards

I do not Understand, I think editing style.css file is useless if not please explain me how can I use this script -- #k2QuickIcons .icon-wrapper:nth-child(4) { display: none; }

I posted the file you need to edit.
You need to use the snippet as a base and hide the elements you need to hide.
www.w3schools.com/cssref/sel_nth-child.asp

It is also possible to override the administration modules as well.
getk2.org/documentation/tutorials/174-templating-with-k2-and-the-concepts-of-sub-templates

This is for the front-end but the same logic applies to the backend templates as well.