If this was available on the Edit menu or if you actually had an Edit
toolbar (there is not one by default), then this functionality was
undoubtedly provided by an add-in of some sort. But you should be able to
accomplish the same thing this way:
1. In the Find (not Replace) dialog, expand the dialog by clicking More.
2. Check the box for "Highlight all items found in" and choose the
appropriate context.
3. Click the Format button and choose Highlight.
4. Leaving the "Find what" box empty, click Find All.
5. Click back in the document window to return the focus to that window; how
you do this is critical: if you click outside the text, the selected items
will be unselected; if you click in one of them, they'll probably stay
selected (this may require some trial and error).
6. Press Ctrl+C to copy all the selected text.
7. Press Ctrl+V to paste it into another document.