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I've iterated through numerous versions of clipboards, from clipboards anchored on item sets to workspaces to work areas. A global clipboard is a lot less confusing then a non-global one: you don't have to either flush the clipboard when switching contexts or deal with clipboards containing content you copied earlier. A global clipboard is also more powerful, as you can allow a workspace to e.g. only paste a string representation. Finally, the basic rule to understand a clipboard stays as simple as you know it from other applications: if the clipboard is there, you can use it, and you can paste an item in the clipboard, if its type is accepted by your currently selected item.
It is not required that every workspace shows the clipboardThe clipboard may be missing in a workspace. It should actually only be shown (i.e. not shown with all buttons disabled), if a workspace can make use of it.
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