The drop-down menu for a layer in the Layer List widget still shows an option to 'Open Attribute Table' after deselecting the Show button next to a layer in the attribute table configuration.
Last Published: July 20, 2018ArcGIS Web AppBuilder for Developers
Bug ID Number
December 3, 2015
August 21, 2020
ArcGIS Web AppBuilder for Developers
Will Not Be Addressed
The development team has considered the issue or request and concluded it will not be addressed. The issue's Additional Information section may contain further explanation.
The Show option in the Attribute Table is designed for indicating the initial state of the layer in Attribute Table. Unchecking it means it's not shown by default when the widget is opened, but you can open it later.