Report works in .Net 4.0, hangs in 4.5

Rexxrally

I have a C# app (originally written in VS2010 .Net 4.0) that uses a Fast Report (V2015.1.1).
It works perfectly.

I upgraded the app using VS2015 to .Net 4.5.

The code still runs fine, generates no errors, opens the window that the Fast Report Viewer is in.
The in-progress bar appears in the window, and that's it. The report never appears. It just hangs with the in-progress bar visible.

Anyone have any ideas why the report is no longer working in .Net 4.5?

ipong

dotnet version is not the issue, i use fastreport .net2 in .net4.5 application.
debug the application and check datasource.