problem with umg

Hello. I get some troubles with my UMG, maybe you can help me.
I’ve got a first UMG-“button”. This UMG"button" has variable / functions / action that i can duplicate as instance in my general UMG. This UMG button act like a button with preset inside.
All the “instances editable” of the UMG-“button” are editable in the general UMG. But the instance of the staticmeshactor doesn’t work. I can choose a staticmesh of my level (all the staticmesh actor are visible in the list) but impossible to validate.
If you have an idea…