Multi selection field on Account Mini page

Hello,

i would like to add a multiple selection field to the mini page when creating a new account.

We still working with classic UI.
For the multiple selection, I am using the add-on
“Multi-select text field setup for Creatio.”

The lookup works, but it is only displayed on half of the mask.
However, when setting up the page, the container is displayed across the entire mask.

Perhaps someone here has an idea for me.

Thank you very much.