I faced two troubles, and the root looks same issue.
UiPath Studio 18.3.2(CE) doesn’t add .NET Framework assembly reference.
Making variable as “System.Windows.Forms.OpenFileDialog” type, we need to refer System.Windows.dll And System.Windows.Forms.dll, but UiPath Studio doesn’t works.
As workaround, We can edit xaml file and add <AssemblyReference> tag directly, but it’s not cool.
Using this method, we need to add assembly “System.Data.DataSetExtensions.dll”, but UiPath Studio doesn’t works.
I tried to add reference from “Imports” pane, but it didn’t work.
I hope this issue will be fixed.
This occured in my environment:
Windows 10 Pro (x64) ver 1803
UiPath 18.3.2(CE) Stable
Activity Versions are;