x64 DLL 프로젝트의 컨트롤이 Visual Studio의 Designer에서 보이지 않는 문제

아래와 같은 질문이 있군요,

윈폼 기반의 응용프로그램 dll 참조와 32,64bit 빌드 관련 문의
; https://www.sysnet.pe.kr/3/0/5484

To prevent possible data loss before loading the designer, the following errors must be resolved:

The variable 'userControl1' is either undeclared or was never assigned.

// Form1.Designer.cs

// ...[생략]...
this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
this.ClientSize = new System.Drawing.Size(431, 317);
this.Controls.Add(this.userControl11);
this.Name = "Form1";
this.Text = "Form1";
this.ResumeLayout(false);
// ...[생략]...

at System.ComponentModel.Design.Serialization.CodeDomSerializerBase.Error(IDesignerSerializationManager manager, String exceptionText, String helpLink)
at System.ComponentModel.Design.Serialization.CodeDomSerializerBase.DeserializeExpression(IDesignerSerializationManager manager, String name, CodeExpression expression)
at System.ComponentModel.Design.Serialization.CodeDomSerializerBase.DeserializeExpression(IDesignerSerializationManager manager, String name, CodeExpression expression)
at System.ComponentModel.Design.Serialization.CodeDomSerializerBase.DeserializeStatement(IDesignerSerializationManager manager, CodeStatement statement)  

private void InitializeComponent()
{
    this.userControl11 = new WindowsFormsControlLibrary1.UserControl1();
    this.SuspendLayout();
    // 
    // userControl11
    // 
    this.userControl11.Location = new System.Drawing.Point(27, 26);
    this.userControl11.Name = "userControl11";
    this.userControl11.Size = new System.Drawing.Size(227, 140);
    this.userControl11.TabIndex = 0;
    // 
    // Form1
    // 
    this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
    this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
    this.ClientSize = new System.Drawing.Size(431, 317);
    this.Controls.Add(this.userControl11);
    this.Name = "Form1";
    this.Text = "Form1";
    this.Load += new System.EventHandler(this.Form1_Load);
    this.ResumeLayout(false);

    this.Text = IntPtr.Size.ToString();
}

#region Component Designer generated code

/// <summary>
/// Required method for Designer support - do not modify 
/// the contents of this method with the code editor.
/// </summary>
private void InitializeComponent()
{
    this.SuspendLayout();
    // 
    // UserControl1
    // 
    this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
    this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
    this.Name = "UserControl1";
    this.Size = new System.Drawing.Size(391, 230);
    this.ResumeLayout(false);

}

#endregion

private void InitializeComponent()
{
    this.SuspendLayout();
    // 
    // UserControl1
    // 
    this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
    this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
    this.Name = "UserControl1";
    this.Size = new System.Drawing.Size(391, 230);
    this.ResumeLayout(false);
    if (string.IsNullOrEmpty(this.Name) != null) { }
}

at Microsoft.VisualStudio.Design.Serialization.CodeDom.XML.CodeDomXmlProcessor.CreateQuoteExpression(XmlElementData xmlElement)
at Microsoft.VisualStudio.Design.Serialization.CodeDom.XML.CodeDomXmlProcessor.XmlElementData.get_CodeDomElement()
at Microsoft.VisualStudio.Design.Serialization.CodeDom.XML.CodeDomXmlProcessor.EndElement(String prefix, String name, String urn)
at Microsoft.VisualStudio.Design.Serialization.CodeDom.XML.CodeDomXmlProcessor.Parse(XmlReader reader)
at Microsoft.VisualStudio.Design.Serialization.CodeDom.XML.CodeDomXmlProcessor.ParseXml(String xmlStream, CodeStatementCollection statementCollection, String fileName, String methodName)
at Microsoft.VisualStudio.Design.Serialization.CodeDom.VSCodeDomParser.OnMethodPopulateStatements(Object sender, EventArgs e)
at System.CodeDom.CodeMemberMethod.get_Statements()
at System.ComponentModel.Design.Serialization.TypeCodeDomSerializer.Deserialize(IDesignerSerializationManager manager, CodeTypeDeclaration declaration)
at System.ComponentModel.Design.Serialization.CodeDomDesignerLoader.PerformLoad(IDesignerSerializationManager manager)
at Microsoft.VisualStudio.Design.Serialization.CodeDom.VSCodeDomDesignerLoader.PerformLoad(IDesignerSerializationManager serializationManager)
--- End of stack trace from previous location where exception was thrown ---
at Microsoft.VisualStudio.Design.Serialization.CodeDom.VSCodeDomDesignerLoader.PerformLoad(IDesignerSerializationManager serializationManager)
at System.ComponentModel.Design.Serialization.BasicDesignerLoader.BeginLoad(IDesignerLoaderHost host) 

Visual Studio x64 implementation - Visual Studio Feedback 12
; https://developercommunity.visualstudio.com/t/visual-studio-x64-implementation/1372671

XAML Designer
; https://devblogs.microsoft.com/visualstudio/improvements-to-xaml-tooling-in-visual-studio-2019-version-16-7-preview-1/#xaml-designer