display exclude button on chosen selection on variable editor

Hi expert

i created a Hierarchy node variable on hierarchy financial statement to allow user to select hierarchy node Fs item and multiple accounts.

the selection option choosen are:

on tab General : type of variable : hierarchy node,processing by : manual input/default Value,ref Cara: Fs item

on tab Details : multiple single values, variable is mandatory, variable is ready for input

it works : i can select multiple node fs item, but the problem is that i can not exclude one account because the square button in red are not display when i select it ?

Do you know if it is possible? and how to do it?

thanks a lot