On ROI Box tab, Custom Label control is added under Show on Center-Top of ROI Box node.
Substitution notation is supported to show greek letter, superscript, subscript, etc.
Calculation is supported too e.g. user can write $(slope*intercept).
Such custom label can be saved in gadget dialog theme and applied to new graph.
Use such ROI box label when generating output label box
E.g. For such multi-layer graph,
Set custom label on ROI Box tab
Set Parameter Table to be Use ROI Box Tab Settings and uncheck all other output on Label Box tab.
Click the > button next to the yellow ROI box and choose New Output for All Layers. Fit curve and label will be added to each layer.
