Copy and pasting legends: When it works, when it doesn't.

Prism graphs can include a legend. This is a symbol (or bar) followed by text that identifies the data set. In some cases you can copy a legend and paste it. In other cases you cannot. 

Copy the entire legend, paste onto a layout to create a master legend

If you select and copy an entire legend, Prism lets you  paste it onto a layout. This lets you create what we call a "master legends" -- a legend that applies to several graphs on the page. 

Once you paste a legend onto a layout, you can change the font, and text size and color. But you cannot edit the text.

Learn more about a master legend.

After copying the entire legend, it is not possible to paste onto a graph

The legend isn't like a text object or a box -- it is connected to a data set, so the appearance will change if you change the size, color, etc of the symbol. It really would not make sense to copy a legend from one graph to another, as that linkage would either be lost or kept, and either way would be confusing much of the way. Prism 4 and 5 simply disallow pasting of a legend onto a graph, to avoid confusion. Prism 3 lets you paste a legend, but then deletes it when it next redraws the graph (since the legend is not connected to any data sets on the graph). It seems as though legends are vanishing.

Copy and pasting the text part of the legend

While it is not possible to copy  an entire legend object and paste it onto a graph, it is possible to copy and paste just the text portion of the legend.  Double-click to edit the legend, select a portion (or all) of the text, and copy to the clipboard Then go to the second graph (or stay on the same one), and paste. You'll paste just the text, not the symbol or bar that precedes the text and defines the legend object.