The icon is also displayed when you are in the technology tree, for example, and then covers it. is that intentional or shouldn't it normally disappear?

This can't easily be fixed since there's no way to know that the client has the tech tree open.

Would it be possible to make the button so that it disappears when you close the General Inventory and becomes visible again when you open the inventory? Could be a solution

Kobani

Would it be possible to make the button so that it disappears when you close the General Inventory and becomes visible again when you open the inventory? Could be a solution

No, the inventory is client-side. The server can't determine whether it's open, nor can it determine when it is opened or closed.