smartedit - renderService: parentOverlay empty for component

Hello experts!

I would like to add a component in a slot, but the latter is "hidden" by another slot and I can't drag and drop on it.

It seems that there are 3 shared NavNodeSlot overlapped and I think this issue can be related to the error displayed in the console: "renderService: parentOverlay empty for component: LPLNavigationMenuComponent". I know also that smartedit refers to a velocity template in order to render the page, but I don't know what exactly causes this problem and how can I fix it.

Any help please?

Ps: I'm running SAP Commerce 19.05.10.