Hi @pamela_king ,
What is the behaviour that we're observing in ArcGIS Web AppBuilder - is symbology being simplified or features are not drawing at all?
In ArcGIS Online, the 'New Map Viewer' is a younger app compared with the 'Map Viewer Classic' app.
Its built on the 4x ArcGIS API for Javascript, whereas the latter is built on the 3x version. And this is why the more recent apps are capable of some more advanced functionality.
The same can be said of web app designers like 'ArcGIS Experience Builder' (4x) and ArcGIS Web AppBuilder (3x). So if we're not seeing parity between functionality of a web map and an app designer interface, it is likely sue to their limitations in development...
Depending on the functionality of your web app, you may be able to re-create it in ArcGIS Experience Builder, in order to preserve the more complex symbology of your web map - however - this app designer does not yet have all the widget capabilities of ArcGIS Web AppBuilder. The 'Experience Builder' development team is aiming for parity with ArcGIS Web AppBuilder, which is why we're incrementally seeing more widgets with each update - BUT, at this stage there is not complete equivalency.
Apologies, all of the above probably doesn't resolve the issue you're encountering. This a bit of a grey area time in development for the New Map Viewer, as they offer a lot of new capabilities but still lack some of the functionality of their older counterparts.
