I want to overwrite the plugin so instead of selecting an item to be shown in an itemlist or in item. I want to show a whole category.

i can easily change linkitem.php line 86
from: $query .= " AND i.id={$id}"; to $query .= " AND c.id={$id}";

but in backend when i go to an item to select a valid category is still shows the select item option.

How can i change that code? Where do i need to make changes?

i just add the plugin code. It's not my code but i will use it to make a little different plugin if its possible.

Also i will publish the code with the the name of the original owner of the plugin and the new plugin will be also free. I want to contribute to K2 because it give us so much in turn.