Rpg Inventory/UMG highlights problem.

Hi

I have a annoying issue with my inventory system. But first I try to show how it works:

When I pickup item in my inventory shows a itembox ( look pic “add inventory box”).
Item box is a simple border with some graphic on it and some text (look pic “inventory”)

The problem is with highlights, now it works into this way, that when I click on one of them and is highlighted, but when I click on another the the one earlier is still highlighted untill I click on him one more time.

I want that when I click on any of them the rest is unhighlighted. I try created binding for itembox (pic “button down” and “button up” but it doesn’t work. Please help!

Anyone? I just need a properly bind onMouseButtonDown and Up…