Field Selector consists of 4
Data Sources- used for selecting data sources that are currently loaded into the IDV.
Formulasis a particular data source for applying formulas to other data sources.
Fields- displays the list of data choices (parameters, formulas) for the selected data source.
Displays- holds the list of display types applicable to the selected field.
Data Subset- depending on the type of data, this panel displays the list of times, levels and spatial subsetting associated with the selected data choice.