Mouse button down not working on umg button

so I’ve been watching this YouTube series…8Tpmj-iWmzqo_Q
I’ve gotten to point were am making an action menu for my inventory only the on mouse button function doesn’t seem to working in 4.18.3
So I’ve tested the code using a on key up function and it works fine so am just wondering if any one knows how I can get right click on a button with out mouse button down