Remember Filled Bar style for graphs between sessions

If a user sets the style for a graph track, de-selects the graph track, and then re-selects it, the setting within the Graph tabbed panel is not properly re-set.

To reproduce:

• Open and load data for a graph track (see A. thaliana genome for examples you can load from the RNA-Seq Quickload data source)
• Select the graph track
• Select Graph tabbed panel
• Select style Filled Bar
• Deselect the track (the graph panel becomes inactive and doesn’t show any settings)
• Re-select the same graph track
• Notice: The graph is still drawn as Filled Bar, the but none of the radio buttons are selected.

If you do the same thing and select any other style, the radio button is still selected when you re-select the graph track.