The dashboard graphs are rendered with Adobe Flash by default. In the coming release of R10f, the dashboard can be rendered without the Flash player. To switch from the default Flash, see the Admin Guide for more information.
There are are advantages to render graphs with the Flash player. The rendering quality is good and it supports the most variety of browsers. However, the graphs rendered by the Flash player are refreshed every time a dashboard tab is switched to. The new rendering engine does not do it.
Here are screenshots of dashboard graphs without the Flash player.