Use case: in the parameter pane, users want to be quickly select all fields or deselect all fields.

Today, users can use Ctrl + A to select all fields w/ in the parameter pane and click anywhere in the whitespace area of the pane to deselect. 

Evaluate if we want to add icons only in parameters pane or in dimension & measure pane as well. Do we introduce 2 icons: existing ADS select all and deselect all? Or maybe a toggle icon that selects all if not everything is selected & then deselects all if all items are selected.