As far as I can see, the deployed application, opened in IE forces the radOrgChart to be rendered in Classic RenderMode. This also forces the Orientation to be Vertical instead of Horizontal.
The problem that you have experienced with RadTreeView also seems to be related to RenderModes, as in Lightweight the expand / collapse sign is a font icon and not an image / sprite (as it is in Classic RM).
The observed issues point to the suggestion that in some way the Compatibility mode is turned on for IE. When in Compatibility mode / view (which is actually IE 7 emulation), the RadOrgChart and the RadTreeView are forced to be rendered in Classic RM.
In case that you observe the problem after openning the local and the deployed version of the application in the same browser, I would suggest you review the settings on server you are deploying on, Which may force the application to run in Compatibility view. Keep in mind that IE 7 (and Compatibility view) are no longer supported
by the Telerik ASP.NET AJAX suite.
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and share your thoughts.