disable closing the data browser

[c-wetzel]

trafficstars

I would very much like to prevent users from closing the data browser. Is there a way to disable / delete the "close" button via iframe export options? The background is that otherwise users first have to click on "See data layers" in the menu bar on the left and then on "browse data" to see the window on the right again. – I am new to the topic and have only built an interactive map via umap.openstreetmap.fr.

This is my current iframe:

[c-wetzel]

I have tried (unsuccessfully) to include a css code line next to the iframe. Could anyone point me to the right direction?

The problem seems to be that umap.openstreetmap.fr is a foreign domain and web-browsers protect cross-content.