Hi Menelaos, the way the Workspace Hierarchy works in GoodData Cloud, the child workspace will inherit all entities present in the parent workspace. The inherited entities are displayed in read-only mode, which would explain why you are unable to edit the inherited reports. You can check out
Build a Workspace Hierarchy more info.
If you have a dashboard that is on a parent but cannot be on a child workspace, I would suggest removing it from the parent workspace and then only adding it to the children that require it, for example.
You can even add another layer to the hierarchy: a pared-down parent with only the things that every child should have > an intermediate child workspace with additional stuff, that you might want to edit > the final, end-user child workspaces. Be careful not to go too deep, though! Anything more than 2 levels deep becomes very difficult to manage.