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POBlack margins appear when expanding form?
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  1. POBlack margins appear when expanding form?
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    copied!<p>Create a .net 2.0 Windows form app, add a splitContainer docked Fill, with this in its form constructor:</p> <pre><code>public Form1() { InitializeComponent(); for (int i = 1; i &lt;= 300; i++) { FlowLayoutPanel f = new FlowLayoutPanel(); f.Dock = DockStyle.Fill; Button b = new Button(); f.Controls.Add(b); splitContainer1.Panel2.Controls.Add(f); } } </code></pre> <p>Press F5. Grab the form by the lower right-hand-edge and drag quickly to expand the form. The form expands rather jerkily due to the work being done in all the controls.</p> <p>I have an app with a form in it with some slow controls which has similarly become slow. The difference is that in my app, I get ugly black space appearing for a fraction of a second in the gaps as I drag out the form with my mouse. The window is not re-drawing properly. This ugly black space does not appear in the sample code above.</p> <p>Any ideas what might cause black space to appear when expanding a slow form?</p> <p>I have tried double-buffered but that makes no difference.</p> <p><strong>EDIT:</strong> I have dismantled the form down to its basics so that this can be reproduced. Start a new C# Windows Form application called WindowsFormsApplication_SampleFault. Paste the code below into the Form1.cs</p> <pre><code>using System; using System.Collections.Generic; using System.Drawing; using System.Reflection; using System.Windows.Forms; using System.Diagnostics; using System.Security.Principal; using System.Runtime.InteropServices; namespace WindowsFormsApplication_SampleFault { public partial class Form1 : Form { public Form1() { InitializeComponent(); for (int i = 1; i &lt;= 200; i++) { Button b = new Button(); b.Dock = DockStyle.Fill; this.Controls.Add(b); } } } } </code></pre> <p>then paste this into Form1.Designer.cs</p> <pre><code>namespace WindowsFormsApplication_SampleFault { partial class Form1 { /// &lt;summary&gt; /// Required designer variable. /// &lt;/summary&gt; private System.ComponentModel.IContainer components = null; /// &lt;summary&gt; /// Clean up any resources being used. /// &lt;/summary&gt; /// &lt;param name="disposing"&gt;true if managed resources should be disposed; otherwise, false.&lt;/param&gt; /// protected override void Dispose(bool disposing) { if (disposing &amp;&amp; (components != null)) { components.Dispose(); } base.Dispose(disposing); } #region Windows Form Designer generated code /// &lt;summary&gt; /// Required method for Designer support - do not modify /// the contents of this method with the code editor. /// &lt;/summary&gt; private void InitializeComponent() { this.statusStrip1 = new System.Windows.Forms.StatusStrip(); this.SuspendLayout(); // // statusStrip1 // this.statusStrip1.Location = new System.Drawing.Point(0, 472); this.statusStrip1.Name = "statusStrip1"; this.statusStrip1.Size = new System.Drawing.Size(756, 22); this.statusStrip1.TabIndex = 6; this.statusStrip1.Text = "statusStrip1"; // // frmOptions // this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F); this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font; this.ClientSize = new System.Drawing.Size(756, 494); this.Controls.Add(this.statusStrip1); this.DoubleBuffered = true; this.ImeMode = System.Windows.Forms.ImeMode.Off; this.MinimizeBox = false; this.MinimumSize = new System.Drawing.Size(750, 500); this.Name = "frmOptions"; this.ShowIcon = false; this.StartPosition = System.Windows.Forms.FormStartPosition.CenterScreen; this.ResumeLayout(false); this.PerformLayout(); } #endregion private System.Windows.Forms.StatusStrip statusStrip1; } } </code></pre> <p>Press F5 and attempt to drag-out the form. Note I am deliberately overloading the redraw mechanism to produce the black areas.</p> <p>I believe that something is wrong with the form designer code but I am not sure what. </p>
 

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