I found that it comes from RaadRibbonView not RadRibbonWindow.
the RadRibbonView need .net4.5 and can not be run in .net 4.
how can i use RadRibbonView in .net4?
Dinko | Tech Support Engineer
answered on 14 Sep 2016, 12:26 PM
We weren't able to reproduce the described error in your post. Basically, our controls will work with both versions of .NET (v4 , v4.5). You can double check if the .NET version of the project matches the version of the DLLs which you have referenced. You can also double check if all referenced DLLs target the same .NET version.
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