Uncaught TypeError in PlotlyGraph via FigureExtractor.js

[umesh-timalsina]

In ExecutionIndex / PlotlyGraph widget, following error is encountered:

Uncaught TypeError: Cannot read property 'getAttribute' of null
    at FigureExtractor.getMetaType (FigureExtractor.js:213)
    at isMetaType (FigureExtractor.js:203)
    at FigureExtractor._getContainmentParentNodeAt (FigureExtractor.js:208)
    at FigureExtractor.getGraphNode (FigureExtractor.js:197)
    at ExecutionIndexControl._getObjectDescriptor (ExecutionIndexControl.js:249)
    at ExecutionIndexControl._onLoad (ExecutionIndexControl.js:335)
    at ExecutionIndexControl._eventCallback (ExecutionIndexControl.js:318)
    at Object.FN (ExecutionIndexControl.js:210)
    at userEvents (client.js:308)
    at _updateTerritoryAllDone (client.js:432)

Will be fixed by #1771.