[Bug]: TreeGridView: Plus/Minus Sign Not Displayed in TreeGrid and Collapse/Expand Behaviors Broken

[Lephat902]

Describe the bug
The plus/minus sign for expanding/collapsing tree nodes is not visible in the KryptonTreeGridView. Additionally, after collapsing and then expanding all nodes, the data structure appears to "flush down" incorrectly.

To Reproduce

1. Set up a KryptonTreeGridView with the following configuration in Form1.designer.cs:

ktgv1.AllowUserToAddRows = false;
ktgv1.AllowUserToDeleteRows = false;
ktgv1.BorderStyle = BorderStyle.None;
ktgv1.ColumnHeadersHeight = 36;
ktgv1.DataSource = null;
ktgv1.Dock = DockStyle.Fill;
ktgv1.EditMode = DataGridViewEditMode.EditProgrammatically;
ktgv1.ImageList = null;
ktgv1.Location = new Point(0, 0);
ktgv1.Name = "ktgv1";
ktgv1.RowHeadersWidth = 51;
ktgv1.Size = new Size(800, 450);
ktgv1.TabIndex = 0;

2. Add a tree structure with nodes in the Form1.cs constructor:

public Form1()
{
    InitializeComponent();

    // Example of adding nodes
    // Define columns
    ktgv1.Columns.Add(new KryptonTreeGridColumn { HeaderText = "name", DataPropertyName = "Column1" });
    ktgv1.Columns.Add(new KryptonDataGridViewTextBoxColumn { HeaderText = "age", DataPropertyName = "Column2" });
    ktgv1.Columns.Add(new KryptonDataGridViewTextBoxColumn { HeaderText = "birthdate", DataPropertyName = "Column3" });
    ktgv1.Columns.Add(new KryptonDataGridViewTextBoxColumn { HeaderText = "job", DataPropertyName = "Column4" });

    var rootNode = ktgv1.GridNodes.Add("Root", "", "", "");
    var childNode1 = rootNode.Nodes.Add("jane doe", "18", "2022-12-12", "engineer");
    var childNode2 = rootNode.Nodes.Add("joe doe", "18", "2022-12-12", "engineer");
    childNode1.Nodes.Add("ch-joe doe", "18", "2022-12-12", "engineer");
    for (int i = 0; i < 3; i++)
    {
        var childNodex = rootNode.Nodes.Add($"ch-joe doe {i}", "18", "2022-12-12", "engineer");
        for (int j = 0; j < 3; j++)
        {
            childNodex.Nodes.Add($"ccx - joe doe {i}", "18", "2022-12-12", "intern");
        }

    }
    ktgv1.ExpandAll();
}

Here is the whole code repository: WinFormsApp1.zip

Expected behavior

• The plus/minus signs for expanding/collapsing nodes should be visible.
• The expand/collapse behavior should function correctly without flushing data.
• After clicking Collapse All and Expand All, the nodes should properly display their states (expanded or collapsed), and the data should remain intact.

Screenshots
Here are some screenshots to clarify:

1. At first it is as below, the plus/minus signs are missing for the expanded nodes:
   
2. Then I click Collapse button at root node, it is this way:
   
3. Then I click Expand All again, it becomes weird:
   

Desktop:

• OS: Windows 11
• Version: 26100.3915
• Framework/.NET Version: 9.0.4
• Toolkit Version: 95.25.4.111

[Lephat902]

I haven't run the whole source code to debug but I read the related code and notice this piece of code, it may be the cause for the wrong row positions in the DataGridView

Currently, I have to use the workaround that is to collapse all the children nodes on NodeCollapsing event but it would be nicer if it can be fixed.

private void ktgv_NodeCollapsing(object sender, Krypton.Toolkit.Suite.Extended.TreeGridView.CollapsingEventArgs e)
{
    foreach (var node in e.Node.Nodes)
    {
        node?.Collapse();
    }
}

[Lephat902]

In my case, to display the +/- correctly, I have to change this piece of code in KryptonTreeGridCell.cs from

// Paint node glyphs
if (node.IsExpanded)
{
    node.Grid.ROpen.DrawBackground(graphics, new Rectangle(glyphRect.X, glyphRect.Y + glyphRect.Height / 2 - 4, 10, 10));
}
else
{
    node.Grid.RClosed.DrawBackground(graphics, new Rectangle(glyphRect.X, glyphRect.Y + glyphRect.Height / 2 - 4, 10, 10));
}

to

var renderer = node.IsExpanded ? node.Grid.ROpen : node.Grid.RClosed;

// Get native size of the glyph
Size nativeSize = renderer.GetPartSize(graphics, ThemeSizeType.True);

// Draw at native size
using Bitmap bmp = new(nativeSize.Width, nativeSize.Height);
using (Graphics gBmp = Graphics.FromImage(bmp))
{
    renderer.DrawBackground(gBmp, new Rectangle(Point.Empty, nativeSize));
}

// Now draw the scaled image to your desired glyph rectangle (10x10)
graphics.DrawImage(
    bmp,
    new Rectangle(glyphRect.X, glyphRect.Y + glyphRect.Height / 2 - 5, 10, 10), // destination
    new Rectangle(0, 0, nativeSize.Width, nativeSize.Height),                   // source
    GraphicsUnit.Pixel
);

I change the code with the help of AI tools, the root cause is the displayed button is actually only the top-left corner of the original image, so that I have to scale it to fit 10x10 rectangle.