Problems with IE and Portal for ArcGIS Web Apps

[CrossrailGIS]

So we have just started experiencing problems with web apps through Portal for ArcGIS 10.5.1 where the header controller widget is failing to load.  The error I am seeing is:

create [themes/FoldableTheme/widgets/HeaderController/Widget] error:Error: Access is denied.

at postCreate (https://xxx/themes/FoldableTheme/widgets/HeaderController/Widget.js?wab_dv=2.1:84:11)

This is only happening on IE, on Firefox it works fine.  Has anyone else experienced this problem?  I've also noticed that this problem is possibly related to a specific build of IE (11.0.9600.19266), we have tried on a couple of other versions of IE (notably 1.0.9600.19236) and this problem does not occur.

Regards

Dan

[RobertBorchert]

IE causes a lot of problems with GIS online.  We do ALL of our work in Portal via Chrome.  

[CrossrailGIS]

Hi Robert,

Indeed and I would if I could but unfortunately Chrome is not permitted where we are, and although Firefox is available, IT have done something to it to make it unworkable!

Sort of thankfully I think I've tracked down the source of the problem (or rather a colleague of mine did), it seems that it's a known issue as per this page:

https://support.esri.com/en/Technical-Article/000020226

Hopefully this might help others who come across this problem...