I returned to check on an ArcGIS Online web app I've been updating sporadically over the last few months to discover that suddenly, with no apparent changes to the app or its underlying web map, a black void has replaced every pane in the web app except for the text-only 'About' pane on the far left.
The issue seems to be that all of the panes/widget views have been shunted down to the very bottom of the app interface - both the editing and "live" view interfaces.
I have been able to return the app to functionality using the app builder's 'edit layout' interface, but one of the default/required widget cells is still forced to the bottom of the screen, causing an unusable empty space to populate above it.
I can minimize this by expanding the usable cells as far to the right of the screen as possible, but the faulty widget cell is still present in the very bottom right of the app screen.
Does anyone have any ideas what causes this formatting error, and how to make sure it doesn't reappear on its own, without redoing the app from scratch?
