...
Delete graphs to permanently remove them from the viewer and from memory. To delete graphs created in IGB, select the graph or graphs, and click the Delete button. Loaded graphs can be delete the same way or, just click the trashcan icon next to the graph file name in the Data Access panel, as you would for an annotation track.
Saving graph tracks
IGB allows you to save individual graph tracks for later use or sharing. This is especially important for graph tracks made in IGB, either through manipulation of your graphs or after using one of IGB's create graph functions. Select the graph track, then in the Graph Adjuster tab, click the Save Selected... button. You will be offered to save the file in .bgr, .sgr or .gr format. Details about these formats is found in File Formats.