窗体不能调整大小

这有点令人沮丧，我一直在研究一个应用程序，突然我不能再通过将鼠标移动到窗体的边缘来调整它的大小。我可以最大化和最小化的标准按钮。

我使用FormBorderStyle = Sizable;

我检查了每一个属性，似乎不能弄清楚我一定是不小心改变了哪个属性。我也可以使用Win+左右键来调整窗体的大小。我怎么也想不出是什么原因引起的。

下面的代码

namespace WindowsFormsApplication1
{
    partial class Form1
    {
        /// <summary>
        /// Required designer variable.
        /// </summary>
        private System.ComponentModel.IContainer components = null;
        /// <summary>
        /// Clean up any resources being used.
        /// </summary>
        /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
        protected override void Dispose(bool disposing)
        {
            if (disposing && (components != null))
            {
                components.Dispose();
            }
            base.Dispose(disposing);
        }
        #region Windows Form 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();
            // 
            // Form1
            // 
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.None;
            this.AutoSizeMode = System.Windows.Forms.AutoSizeMode.GrowAndShrink;
            this.ClientSize = new System.Drawing.Size(778, 545);
            this.Font = new System.Drawing.Font("Times New Roman", 12F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0)));
            this.Margin = new System.Windows.Forms.Padding(4);
            this.Name = "Form1";
            this.Text = "Form1";
            this.ResumeLayout(false);
        }
        #endregion

    }
}

this.AutoSizeMode = System.Windows.Forms.AutoSizeMode.GrowAndShrink;