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The name of this "panel" is minimap.
You can change the visibility of it by changing your file Settings.json and adding a key-value pair with the key editor.minimap.enabled
and a value boolean.
This setting can be valid for all workspaces, if you value in tab user Settings, or just for the Workspace current, edit in the tab Workspace Settings.
To open the edition of this file, press Ctrl + , (comma).
"editor.minimap.enabled": false