Using the Batch Attribute Editor in a Web App, Can you use the select by point option in conjunction with holding down a keyboard key to specifically select certain features? The batch attribute editor freehand polygon tool works in this manner, but it's a bit cumbersome. Looking to select features for batch attribute editing like adding to the selection or like the selection button works in conjunction with the shift key in ArcMap. In a Web App, the Select Widget using the Select By Circle options works this way, but then you don't have the option to edit, let alone batch edit.
Did you ever find an answer to this questions? I too have the same issue. I want my users to be able to select multiple features and calculate them all at one time. The options for selecting in the Batch Attribute Editor widget are limited. Not sure how to accomplish this using WAB and AGOL.