fixup! Add global usings and plumb through the WPF

Author: RussKie

pkg/Microsoft.Private.Winforms/sdk/dotnet-wpf/System.Windows.Forms.GlobalUsings.props

@@ -6,15 +6,25 @@
    -->
 
 <Project>
-
-  <ItemGroup Condition=" '$(UseWindowsForms)' == 'true' ">
-    <!--
-      SDK defines the following global usings:
-      * System
-      * System.Collections.Generic
-      * System.Linq
-      * System.Threading.Tasks
+  <!--
+    ============================================================
+                                     GenerateImplicitNamespaceImports
+    Generates implicit namespace imports source to intermediate directory for C# projects
+    ============================================================
     -->
+  <PropertyGroup>
+    <DisableImplicitNamespaceImports_WindowsForms
+        Condition="'$(DisableImplicitNamespaceImports_WindowsForms)' == '' and '$(DisableImplicitNamespaceImports)' != 'true'">false</DisableImplicitNamespaceImports_WindowsForms>
+  </PropertyGroup>
+
+  <ItemGroup Condition=" '$(DisableImplicitNamespaceImports_DotNet)' != 'true'
+                      and '$(TargetFrameworkIdentifier)' == '.NETCoreApp'
+                      and $([MSBuild]::VersionGreaterThanOrEquals($(_TargetFrameworkVersionWithoutV), '6.0'))
+                      and '$(UseWindowsForms)' == 'true'">
+    <Import Include="System" />
+    <Import Include="System.Collections.Generic" />
+    <Import Include="System.IO" />
+    <Import Include="System.Linq" />
     <Import Include="System.Drawing" />
     <Import Include="System.Windows.Forms" />
   </ItemGroup>