Visual Studio WinForms コード自動生成の挙動

WinFormsのデザイナでコントロールを配置したりすると`*.Designer.cs`というファイルに自動生成コードが記述されます。
この自動生成コードは変な癖があって、特にバージョン管理をしていると意図せず記述が変化して戸惑ってしまう事があります。
#新規作成
こんな画面を作ります。
Visual Studio 2019 / .NET Framework 4.0
![image.png](https://qiita-image-store.s3.ap-northeast-1.amazonaws.com/0/149140/8f084cec-3187-9df1-bc20-0e2b4ad53d2b.png)
button4, button5, button6はPanel上に配置されています。
![image.png](https://qiita-image-store.s3.ap-northeast-1.amazonaws.com/0/149140/1471ec96-da19-f912-246b-753812ca300f.png)
button13, button14, button15はtabPage2内のPanel上に配置されています。

```csharp:Form1.Designer.cs
namespace LayoutSample
{
    partial class Form1
    {
        /// <summary>
        /// 必要なデザイナー変数です。
        /// </summary>
        private System.ComponentModel.IContainer components = null;

        /// <summary>
        /// 使用中のリソースをすべてクリーンアップします。
        /// </summary>
        /// <param name="disposing">マネージド リソースを破棄する場合は true を指定し、その他の場合は false を指定します。</param>
        protected override void Dispose(bool disposing)
        {
            if (disposing && (components != null))
            {
                components.Dispose();
            }
            base.Dispose(disposing);
        }

        #region Windows フォーム デザイナーで生成されたコード

        /// <summary>
        /// デザイナー サポートに必要なメソッドです。このメソッドの内容を
        /// コード エディターで変更しないでください。
        /// </summary>
        private void InitializeComponent()
        {
            this.components = new System.ComponentModel.Container();
            this.menuStrip1 = new System.Windows.Forms.MenuStrip();
            this.toolStripMenuItem1 = new System.Windows.Forms.ToolStripMenuItem();
            this.toolStripMenuItem2 = new System.Windows.Forms.ToolStripMenuItem();
            this.toolStripMenuItem3 = new System.Windows.Forms.ToolStripMenuItem();
            this.toolStripMenuItem4 = new System.Windows.Forms.ToolStripMenuItem();
            this.toolStripMenuItem5 = new System.Windows.Forms.ToolStripMenuItem();
            this.toolStripMenuItem6 = new System.Windows.Forms.ToolStripMenuItem();
            this.button1 = new System.Windows.Forms.Button();
            this.button2 = new System.Windows.Forms.Button();
            this.button3 = new System.Windows.Forms.Button();
            this.panel1 = new System.Windows.Forms.Panel();
            this.button4 = new System.Windows.Forms.Button();
            this.button5 = new System.Windows.Forms.Button();
            this.button6 = new System.Windows.Forms.Button();
            this.button7 = new System.Windows.Forms.Button();
            this.button8 = new System.Windows.Forms.Button();
            this.button9 = new System.Windows.Forms.Button();
            this.tabControl1 = new System.Windows.Forms.TabControl();
            this.tabPage1 = new System.Windows.Forms.TabPage();
            this.button10 = new System.Windows.Forms.Button();
            this.button11 = new System.Windows.Forms.Button();
            this.button12 = new System.Windows.Forms.Button();
            this.tabPage2 = new System.Windows.Forms.TabPage();
            this.panel2 = new System.Windows.Forms.Panel();
            this.button13 = new System.Windows.Forms.Button();
            this.button14 = new System.Windows.Forms.Button();
            this.button15 = new System.Windows.Forms.Button();
            this.button16 = new System.Windows.Forms.Button();
            this.button17 = new System.Windows.Forms.Button();
            this.button18 = new System.Windows.Forms.Button();
            this.statusStrip1 = new System.Windows.Forms.StatusStrip();
            this.toolStripStatusLabel1 = new System.Windows.Forms.ToolStripStatusLabel();
            this.toolStripStatusLabel2 = new System.Windows.Forms.ToolStripStatusLabel();
            this.toolStripStatusLabel3 = new System.Windows.Forms.ToolStripStatusLabel();
            this.contextMenuStrip1 = new System.Windows.Forms.ContextMenuStrip(this.components);
            this.toolStripMenuItem7 = new System.Windows.Forms.ToolStripMenuItem();
            this.toolStripMenuItem8 = new System.Windows.Forms.ToolStripMenuItem();
            this.toolStripMenuItem9 = new System.Windows.Forms.ToolStripMenuItem();
            this.openFileDialog1 = new System.Windows.Forms.OpenFileDialog();
            this.saveFileDialog1 = new System.Windows.Forms.SaveFileDialog();
            this.menuStrip1.SuspendLayout();
            this.panel1.SuspendLayout();
            this.tabControl1.SuspendLayout();
            this.tabPage1.SuspendLayout();
            this.tabPage2.SuspendLayout();
            this.panel2.SuspendLayout();
            this.statusStrip1.SuspendLayout();
            this.contextMenuStrip1.SuspendLayout();
            this.SuspendLayout();
            // 
            // menuStrip1
            // 
            this.menuStrip1.Items.AddRange(new System.Windows.Forms.ToolStripItem[] {
            this.toolStripMenuItem1,
            this.toolStripMenuItem4});
            this.menuStrip1.Location = new System.Drawing.Point(0, 0);
            this.menuStrip1.Name = "menuStrip1";
            this.menuStrip1.Size = new System.Drawing.Size(800, 24);
            this.menuStrip1.TabIndex = 0;
            this.menuStrip1.Text = "menuStrip1";
            // 
            // toolStripMenuItem1
            // 
            this.toolStripMenuItem1.DropDownItems.AddRange(new System.Windows.Forms.ToolStripItem[] {
            this.toolStripMenuItem2,
            this.toolStripMenuItem3});
            this.toolStripMenuItem1.Name = "toolStripMenuItem1";
            this.toolStripMenuItem1.Size = new System.Drawing.Size(25, 20);
            this.toolStripMenuItem1.Text = "1";
            // 
            // toolStripMenuItem2
            // 
            this.toolStripMenuItem2.Name = "toolStripMenuItem2";
            this.toolStripMenuItem2.Size = new System.Drawing.Size(180, 22);
            this.toolStripMenuItem2.Text = "2";
            // 
            // toolStripMenuItem3
            // 
            this.toolStripMenuItem3.Name = "toolStripMenuItem3";
            this.toolStripMenuItem3.Size = new System.Drawing.Size(180, 22);
            this.toolStripMenuItem3.Text = "3";
            // 
            // toolStripMenuItem4
            // 
            this.toolStripMenuItem4.DropDownItems.AddRange(new System.Windows.Forms.ToolStripItem[] {
            this.toolStripMenuItem5,
            this.toolStripMenuItem6});
            this.toolStripMenuItem4.Name = "toolStripMenuItem4";
            this.toolStripMenuItem4.Size = new System.Drawing.Size(25, 20);
            this.toolStripMenuItem4.Text = "4";
            // 
            // toolStripMenuItem5
            // 
            this.toolStripMenuItem5.Name = "toolStripMenuItem5";
            this.toolStripMenuItem5.Size = new System.Drawing.Size(180, 22);
            this.toolStripMenuItem5.Text = "5";
            // 
            // toolStripMenuItem6
            // 
            this.toolStripMenuItem6.Name = "toolStripMenuItem6";
            this.toolStripMenuItem6.Size = new System.Drawing.Size(180, 22);
            this.toolStripMenuItem6.Text = "6";
            // 
            // button1
            // 
            this.button1.Location = new System.Drawing.Point(12, 27);
            this.button1.Name = "button1";
            this.button1.Size = new System.Drawing.Size(75, 23);
            this.button1.TabIndex = 1;
            this.button1.Text = "button1";
            this.button1.UseVisualStyleBackColor = true;
            // 
            // button2
            // 
            this.button2.Location = new System.Drawing.Point(93, 27);
            this.button2.Name = "button2";
            this.button2.Size = new System.Drawing.Size(75, 23);
            this.button2.TabIndex = 2;
            this.button2.Text = "button2";
            this.button2.UseVisualStyleBackColor = true;
            // 
            // button3
            // 
            this.button3.Location = new System.Drawing.Point(174, 27);
            this.button3.Name = "button3";
            this.button3.Size = new System.Drawing.Size(75, 23);
            this.button3.TabIndex = 3;
            this.button3.Text = "button3";
            this.button3.UseVisualStyleBackColor = true;
            // 
            // panel1
            // 
            this.panel1.Controls.Add(this.button6);
            this.panel1.Controls.Add(this.button5);
            this.panel1.Controls.Add(this.button4);
            this.panel1.Location = new System.Drawing.Point(12, 56);
            this.panel1.Name = "panel1";
            this.panel1.Size = new System.Drawing.Size(776, 152);
            this.panel1.TabIndex = 4;
            // 
            // button4
            // 
            this.button4.Location = new System.Drawing.Point(3, 3);
            this.button4.Name = "button4";
            this.button4.Size = new System.Drawing.Size(75, 23);
            this.button4.TabIndex = 0;
            this.button4.Text = "button4";
            this.button4.UseVisualStyleBackColor = true;
            // 
            // button5
            // 
            this.button5.Location = new System.Drawing.Point(84, 3);
            this.button5.Name = "button5";
            this.button5.Size = new System.Drawing.Size(75, 23);
            this.button5.TabIndex = 1;
            this.button5.Text = "button5";
            this.button5.UseVisualStyleBackColor = true;
            // 
            // button6
            // 
            this.button6.Location = new System.Drawing.Point(165, 3);
            this.button6.Name = "button6";
            this.button6.Size = new System.Drawing.Size(75, 23);
            this.button6.TabIndex = 2;
            this.button6.Text = "button6";
            this.button6.UseVisualStyleBackColor = true;
            // 
            // button7
            // 
            this.button7.Location = new System.Drawing.Point(12, 214);
            this.button7.Name = "button7";
            this.button7.Size = new System.Drawing.Size(75, 23);
            this.button7.TabIndex = 5;
            this.button7.Text = "button7";
            this.button7.UseVisualStyleBackColor = true;
            // 
            // button8
            // 
            this.button8.Location = new System.Drawing.Point(93, 214);
            this.button8.Name = "button8";
            this.button8.Size = new System.Drawing.Size(75, 23);
            this.button8.TabIndex = 6;
            this.button8.Text = "button8";
            this.button8.UseVisualStyleBackColor = true;
            // 
            // button9
            // 
            this.button9.Location = new System.Drawing.Point(174, 214);
            this.button9.Name = "button9";
            this.button9.Size = new System.Drawing.Size(75, 23);
            this.button9.TabIndex = 7;
            this.button9.Text = "button9";
            this.button9.UseVisualStyleBackColor = true;
            // 
            // tabControl1
            // 
            this.tabControl1.Controls.Add(this.tabPage1);
            this.tabControl1.Controls.Add(this.tabPage2);
            this.tabControl1.Location = new System.Drawing.Point(12, 243);
            this.tabControl1.Name = "tabControl1";
            this.tabControl1.SelectedIndex = 0;
            this.tabControl1.Size = new System.Drawing.Size(776, 153);
            this.tabControl1.TabIndex = 8;
            // 
            // tabPage1
            // 
            this.tabPage1.Controls.Add(this.button12);
            this.tabPage1.Controls.Add(this.button11);
            this.tabPage1.Controls.Add(this.button10);
            this.tabPage1.Location = new System.Drawing.Point(4, 22);
            this.tabPage1.Name = "tabPage1";
            this.tabPage1.Padding = new System.Windows.Forms.Padding(3);
            this.tabPage1.Size = new System.Drawing.Size(768, 137);
            this.tabPage1.TabIndex = 0;
            this.tabPage1.Text = "tabPage1";
            this.tabPage1.UseVisualStyleBackColor = true;
            // 
            // button10
            // 
            this.button10.Location = new System.Drawing.Point(6, 6);
            this.button10.Name = "button10";
            this.button10.Size = new System.Drawing.Size(75, 23);
            this.button10.TabIndex = 0;
            this.button10.Text = "button10";
            this.button10.UseVisualStyleBackColor = true;
            // 
            // button11
            // 
            this.button11.Location = new System.Drawing.Point(87, 6);
            this.button11.Name = "button11";
            this.button11.Size = new System.Drawing.Size(75, 23);
            this.button11.TabIndex = 1;
            this.button11.Text = "button11";
            this.button11.UseVisualStyleBackColor = true;
            // 
            // button12
            // 
            this.button12.Location = new System.Drawing.Point(168, 6);
            this.button12.Name = "button12";
            this.button12.Size = new System.Drawing.Size(75, 23);
            this.button12.TabIndex = 2;
            this.button12.Text = "button12";
            this.button12.UseVisualStyleBackColor = true;
            // 
            // tabPage2
            // 
            this.tabPage2.Controls.Add(this.panel2);
            this.tabPage2.Location = new System.Drawing.Point(4, 22);
            this.tabPage2.Name = "tabPage2";
            this.tabPage2.Size = new System.Drawing.Size(768, 127);
            this.tabPage2.TabIndex = 1;
            this.tabPage2.Text = "tabPage2";
            this.tabPage2.UseVisualStyleBackColor = true;
            // 
            // panel2
            // 
            this.panel2.Controls.Add(this.button15);
            this.panel2.Controls.Add(this.button14);
            this.panel2.Controls.Add(this.button13);
            this.panel2.Dock = System.Windows.Forms.DockStyle.Fill;
            this.panel2.Location = new System.Drawing.Point(0, 0);
            this.panel2.Name = "panel2";
            this.panel2.Size = new System.Drawing.Size(768, 127);
            this.panel2.TabIndex = 0;
            // 
            // button13
            // 
            this.button13.Location = new System.Drawing.Point(3, 3);
            this.button13.Name = "button13";
            this.button13.Size = new System.Drawing.Size(75, 23);
            this.button13.TabIndex = 0;
            this.button13.Text = "button13";
            this.button13.UseVisualStyleBackColor = true;
            // 
            // button14
            // 
            this.button14.Location = new System.Drawing.Point(84, 3);
            this.button14.Name = "button14";
            this.button14.Size = new System.Drawing.Size(75, 23);
            this.button14.TabIndex = 1;
            this.button14.Text = "button14";
            this.button14.UseVisualStyleBackColor = true;
            // 
            // button15
            // 
            this.button15.Location = new System.Drawing.Point(165, 3);
            this.button15.Name = "button15";
            this.button15.Size = new System.Drawing.Size(75, 23);
            this.button15.TabIndex = 2;
            this.button15.Text = "button15";
            this.button15.UseVisualStyleBackColor = true;
            // 
            // button16
            // 
            this.button16.Location = new System.Drawing.Point(12, 402);
            this.button16.Name = "button16";
            this.button16.Size = new System.Drawing.Size(75, 23);
            this.button16.TabIndex = 9;
            this.button16.Text = "button16";
            this.button16.UseVisualStyleBackColor = true;
            // 
            // button17
            // 
            this.button17.Location = new System.Drawing.Point(93, 402);
            this.button17.Name = "button17";
            this.button17.Size = new System.Drawing.Size(75, 23);
            this.button17.TabIndex = 10;
            this.button17.Text = "button17";
            this.button17.UseVisualStyleBackColor = true;
            // 
            // button18
            // 
            this.button18.Location = new System.Drawing.Point(174, 402);
            this.button18.Name = "button18";
            this.button18.Size = new System.Drawing.Size(75, 23);
            this.button18.TabIndex = 11;
            this.button18.Text = "button18";
            this.button18.UseVisualStyleBackColor = true;
            // 
            // statusStrip1
            // 
            this.statusStrip1.Items.AddRange(new System.Windows.Forms.ToolStripItem[] {
            this.toolStripStatusLabel1,
            this.toolStripStatusLabel2,
            this.toolStripStatusLabel3});
            this.statusStrip1.Location = new System.Drawing.Point(0, 428);
            this.statusStrip1.Name = "statusStrip1";
            this.statusStrip1.Size = new System.Drawing.Size(800, 22);
            this.statusStrip1.TabIndex = 12;
            this.statusStrip1.Text = "statusStrip1";
            // 
            // toolStripStatusLabel1
            // 
            this.toolStripStatusLabel1.Name = "toolStripStatusLabel1";
            this.toolStripStatusLabel1.Size = new System.Drawing.Size(118, 17);
            this.toolStripStatusLabel1.Text = "toolStripStatusLabel1";
            // 
            // toolStripStatusLabel2
            // 
            this.toolStripStatusLabel2.Name = "toolStripStatusLabel2";
            this.toolStripStatusLabel2.Size = new System.Drawing.Size(118, 17);
            this.toolStripStatusLabel2.Text = "toolStripStatusLabel2";
            // 
            // toolStripStatusLabel3
            // 
            this.toolStripStatusLabel3.Name = "toolStripStatusLabel3";
            this.toolStripStatusLabel3.Size = new System.Drawing.Size(118, 17);
            this.toolStripStatusLabel3.Text = "toolStripStatusLabel3";
            // 
            // contextMenuStrip1
            // 
            this.contextMenuStrip1.Items.AddRange(new System.Windows.Forms.ToolStripItem[] {
            this.toolStripMenuItem7,
            this.toolStripMenuItem8,
            this.toolStripMenuItem9});
            this.contextMenuStrip1.Name = "contextMenuStrip1";
            this.contextMenuStrip1.Size = new System.Drawing.Size(81, 70);
            // 
            // toolStripMenuItem7
            // 
            this.toolStripMenuItem7.Name = "toolStripMenuItem7";
            this.toolStripMenuItem7.Size = new System.Drawing.Size(80, 22);
            this.toolStripMenuItem7.Text = "7";
            // 
            // toolStripMenuItem8
            // 
            this.toolStripMenuItem8.Name = "toolStripMenuItem8";
            this.toolStripMenuItem8.Size = new System.Drawing.Size(80, 22);
            this.toolStripMenuItem8.Text = "8";
            // 
            // toolStripMenuItem9
            // 
            this.toolStripMenuItem9.Name = "toolStripMenuItem9";
            this.toolStripMenuItem9.Size = new System.Drawing.Size(80, 22);
            this.toolStripMenuItem9.Text = "9";
            // 
            // openFileDialog1
            // 
            this.openFileDialog1.FileName = "openFileDialog1";
            // 
            // Form1
            // 
            this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 12F);
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
            this.ClientSize = new System.Drawing.Size(800, 450);
            this.Controls.Add(this.statusStrip1);
            this.Controls.Add(this.button18);
            this.Controls.Add(this.button17);
            this.Controls.Add(this.button16);
            this.Controls.Add(this.tabControl1);
            this.Controls.Add(this.button9);
            this.Controls.Add(this.button8);
            this.Controls.Add(this.button7);
            this.Controls.Add(this.panel1);
            this.Controls.Add(this.button3);
            this.Controls.Add(this.button2);
            this.Controls.Add(this.button1);
            this.Controls.Add(this.menuStrip1);
            this.MainMenuStrip = this.menuStrip1;
            this.Name = "Form1";
            this.Text = "Form1";
            this.menuStrip1.ResumeLayout(false);
            this.menuStrip1.PerformLayout();
            this.panel1.ResumeLayout(false);
            this.tabControl1.ResumeLayout(false);
            this.tabPage1.ResumeLayout(false);
            this.tabPage2.ResumeLayout(false);
            this.panel2.ResumeLayout(false);
            this.statusStrip1.ResumeLayout(false);
            this.statusStrip1.PerformLayout();
            this.contextMenuStrip1.ResumeLayout(false);
            this.ResumeLayout(false);
            this.PerformLayout();

        }

        #endregion

        private System.Windows.Forms.MenuStrip menuStrip1;
        private System.Windows.Forms.ToolStripMenuItem toolStripMenuItem1;
        private System.Windows.Forms.ToolStripMenuItem toolStripMenuItem2;
        private System.Windows.Forms.ToolStripMenuItem toolStripMenuItem3;
        private System.Windows.Forms.ToolStripMenuItem toolStripMenuItem4;
        private System.Windows.Forms.ToolStripMenuItem toolStripMenuItem5;
        private System.Windows.Forms.ToolStripMenuItem toolStripMenuItem6;
        private System.Windows.Forms.Button button1;
        private System.Windows.Forms.Button button2;
        private System.Windows.Forms.Button button3;
        private System.Windows.Forms.Panel panel1;
        private System.Windows.Forms.Button button6;
        private System.Windows.Forms.Button button5;
        private System.Windows.Forms.Button button4;
        private System.Windows.Forms.Button button7;
        private System.Windows.Forms.Button button8;
        private System.Windows.Forms.Button button9;
        private System.Windows.Forms.TabControl tabControl1;
        private System.Windows.Forms.TabPage tabPage1;
        private System.Windows.Forms.Button button12;
        private System.Windows.Forms.Button button11;
        private System.Windows.Forms.Button button10;
        private System.Windows.Forms.TabPage tabPage2;
        private System.Windows.Forms.Panel panel2;
        private System.Windows.Forms.Button button15;
        private System.Windows.Forms.Button button14;
        private System.Windows.Forms.Button button13;
        private System.Windows.Forms.Button button16;
        private System.Windows.Forms.Button button17;
        private System.Windows.Forms.Button button18;
        private System.Windows.Forms.StatusStrip statusStrip1;
        private System.Windows.Forms.ToolStripStatusLabel toolStripStatusLabel1;
        private System.Windows.Forms.ToolStripStatusLabel toolStripStatusLabel2;
        private System.Windows.Forms.ToolStripStatusLabel toolStripStatusLabel3;
        private System.Windows.Forms.ContextMenuStrip contextMenuStrip1;
        private System.Windows.Forms.ToolStripMenuItem toolStripMenuItem7;
        private System.Windows.Forms.ToolStripMenuItem toolStripMenuItem8;
        private System.Windows.Forms.ToolStripMenuItem toolStripMenuItem9;
        private System.Windows.Forms.OpenFileDialog openFileDialog1;
        private System.Windows.Forms.SaveFileDialog saveFileDialog1;
    }
}
```
#適当なイベントメソッドを作成
Form.Loadメソッドをデザイナで作成した後に削除して保存

```csharp:Form1.Designer.cs
        // ...

        /// <summary>
        /// デザイナー サポートに必要なメソッドです。このメソッドの内容を
        /// コード エディターで変更しないでください。
        /// </summary>
        private void InitializeComponent()
        {
            // ...

            this.panel1 = new System.Windows.Forms.Panel();
            this.button6 = new System.Windows.Forms.Button();
            this.button5 = new System.Windows.Forms.Button();
            this.button4 = new System.Windows.Forms.Button();

            // ...

            this.tabPage1 = new System.Windows.Forms.TabPage();
            this.button12 = new System.Windows.Forms.Button();
            this.button11 = new System.Windows.Forms.Button();
            this.button10 = new System.Windows.Forms.Button();
            this.tabPage2 = new System.Windows.Forms.TabPage();
            this.panel2 = new System.Windows.Forms.Panel();
            this.button15 = new System.Windows.Forms.Button();
            this.button14 = new System.Windows.Forms.Button();
            this.button13 = new System.Windows.Forms.Button();

            // ...

            // 
            // toolStripMenuItem2
            // 
            this.toolStripMenuItem2.Name = "toolStripMenuItem2";
            this.toolStripMenuItem2.Size = new System.Drawing.Size(80, 22);
            this.toolStripMenuItem2.Text = "2";
            // 
            // toolStripMenuItem3
            // 
            this.toolStripMenuItem3.Name = "toolStripMenuItem3";
            this.toolStripMenuItem3.Size = new System.Drawing.Size(80, 22);
            this.toolStripMenuItem3.Text = "3";
            // 
            // toolStripMenuItem4
            // 
            this.toolStripMenuItem4.DropDownItems.AddRange(new System.Windows.Forms.ToolStripItem[] {
            this.toolStripMenuItem5,
            this.toolStripMenuItem6});
            this.toolStripMenuItem4.Name = "toolStripMenuItem4";
            this.toolStripMenuItem4.Size = new System.Drawing.Size(25, 20);
            this.toolStripMenuItem4.Text = "4";
            // 
            // toolStripMenuItem5
            // 
            this.toolStripMenuItem5.Name = "toolStripMenuItem5";
            this.toolStripMenuItem5.Size = new System.Drawing.Size(80, 22);
            this.toolStripMenuItem5.Text = "5";
            // 
            // toolStripMenuItem6
            // 
            this.toolStripMenuItem6.Name = "toolStripMenuItem6";
            this.toolStripMenuItem6.Size = new System.Drawing.Size(80, 22);
            this.toolStripMenuItem6.Text = "6";

            // ...

            // 
            // button6
            // 
            this.button6.Location = new System.Drawing.Point(165, 3);
            this.button6.Name = "button6";
            this.button6.Size = new System.Drawing.Size(75, 23);
            this.button6.TabIndex = 2;
            this.button6.Text = "button6";
            this.button6.UseVisualStyleBackColor = true;
            // 
            // button5
            // 
            this.button5.Location = new System.Drawing.Point(84, 3);
            this.button5.Name = "button5";
            this.button5.Size = new System.Drawing.Size(75, 23);
            this.button5.TabIndex = 1;
            this.button5.Text = "button5";
            this.button5.UseVisualStyleBackColor = true;
            // 
            // button4
            // 
            this.button4.Location = new System.Drawing.Point(3, 3);
            this.button4.Name = "button4";
            this.button4.Size = new System.Drawing.Size(75, 23);
            this.button4.TabIndex = 0;
            this.button4.Text = "button4";
            this.button4.UseVisualStyleBackColor = true;

            // ...

            // 
            // button12
            // 
            this.button12.Location = new System.Drawing.Point(168, 6);
            this.button12.Name = "button12";
            this.button12.Size = new System.Drawing.Size(75, 23);
            this.button12.TabIndex = 2;
            this.button12.Text = "button12";
            this.button12.UseVisualStyleBackColor = true;
            // 
            // button11
            // 
            this.button11.Location = new System.Drawing.Point(87, 6);
            this.button11.Name = "button11";
            this.button11.Size = new System.Drawing.Size(75, 23);
            this.button11.TabIndex = 1;
            this.button11.Text = "button11";
            this.button11.UseVisualStyleBackColor = true;
            // 
            // button10
            // 
            this.button10.Location = new System.Drawing.Point(6, 6);
            this.button10.Name = "button10";
            this.button10.Size = new System.Drawing.Size(75, 23);
            this.button10.TabIndex = 0;
            this.button10.Text = "button10";
            this.button10.UseVisualStyleBackColor = true;

            // ...

            // 
            // button15
            // 
            this.button15.Location = new System.Drawing.Point(165, 3);
            this.button15.Name = "button15";
            this.button15.Size = new System.Drawing.Size(75, 23);
            this.button15.TabIndex = 2;
            this.button15.Text = "button15";
            this.button15.UseVisualStyleBackColor = true;
            // 
            // button14
            // 
            this.button14.Location = new System.Drawing.Point(84, 3);
            this.button14.Name = "button14";
            this.button14.Size = new System.Drawing.Size(75, 23);
            this.button14.TabIndex = 1;
            this.button14.Text = "button14";
            this.button14.UseVisualStyleBackColor = true;
            // 
            // button13
            // 
            this.button13.Location = new System.Drawing.Point(3, 3);
            this.button13.Name = "button13";
            this.button13.Size = new System.Drawing.Size(75, 23);
            this.button13.TabIndex = 0;
            this.button13.Text = "button13";
            this.button13.UseVisualStyleBackColor = true;

            // ...
```
PanelやTabPage内のメンバーの記述順序が降順になりました。下部にある宣言部の順序は変わりません。
又、何故かToolStripMenuItemのWidthが180から変化します。
#ToolStripMenuItemにイベントを作成して保存
更に、トップレベル以外のToolStripMenuItem.Clickメソッドをデザイナで作成した後に保存すると

```csharp:Form1.Designer.cs
            // ...

            // 
            // toolStripMenuItem2
            // 
            this.toolStripMenuItem2.Name = "toolStripMenuItem2";
            this.toolStripMenuItem2.Size = new System.Drawing.Size(180, 22);
            this.toolStripMenuItem2.Text = "2";
            // 
            // toolStripMenuItem3
            // 
            this.toolStripMenuItem3.Name = "toolStripMenuItem3";
            this.toolStripMenuItem3.Size = new System.Drawing.Size(180, 22);
            this.toolStripMenuItem3.Text = "3";

            // ...
```
ToolStripMenuItemのWidthが180に戻ります。
ちなみにUserControlをプロジェクト内で作成してビルドした時も作成直後とその後のデザイナでの操作により変化します。
デザイナ上で最前面／最背面へ移動等の機能を使った場合にも変化します(これは本来の挙動であって癖ではないはず)。
又、デザイナを開いたままビルドすると、同じプロジェクトでビルドされるユーザー コントロールが含まれている場合、それらの順序も変化します(デザイナを閉じていると変化しない)。
#対処法
デザイナを使用してコントロールを操作したら、最後にFormの適当なイベントメソッドを作成・削除してから保存する。
ビルドする時にはデザイナ ウィンドウは閉じる。
他にも方法があるかもしれません。