DNA GraphPack plugin

Open a sequence object in sequence view and click "Graphs->GC Content (%)" item in popup menu.

A new widget with a graph will appear right above the sequence overview widget:

All graphs are always aligned to the range shown in sequence overview widget. It means that if you change the visible range in overview (either by zooming or scrolling) the content of the graph widget will also be updated.

The most of the graphs use window averaging algorithms to calculate point values. Use "Properties" graph's context menu to change the 'window' and 'window-step' settings.

You can enable multiple graphs by clicking corresponding "Graphs" menu items.

To close graph widget uncheck its item in the "Graph" menu.

Note that some graphs like "GC content (%)" are available only for nucleic sequences.