Graphs look fine in device/graphs area, NaN in graph tree

[yottabite]

I've recently been playing with the Percona MySQL templates (http://www.percona.com/doc/percona-moni ... lates.html) and have not had much luck so far.
At this point I've got graph data (finally!) in the device/graph view, but unfortunately when I look at the graph tree, all of the working graphs show "NaN".
To further confuse things, when I look at the preview view, the data is there, and I am also able to drill down into each of them.

I'm assuming that I have missed something terribly obvious, and have tried adding the graphs to the tree both by adding the device to a sub-tree, as well as by adding all of the graphs to a different sub-tree.

[yottabite]

And of course, it was a fairly easy issue to resolve...

If this happens to anyone, the easy solution for me was to revert back to the "Last Day" preset in graph tree view, instead of the custom view that I had loaded for a different host. During the time that I had specified, there was no data captured (as this was a recently added host).