I have been upgrading an existing .NET Windows Mobile application to use the 3.5 version of the compact framework and to run on Windows Mobile 6.5. I have a form with a TreeView. The TreeView.Checkboxes property is set to true so that each node has a check box. This gives no trouble in all previous versions of Windows Mobile. However, in version 6.5 when you click on a check box it appears to check and then uncheck instantaneously. But it only raises the AfterCheck event once. The only way I can get a check to stick is by double clicking it (which is the wrong behavior). Has anyone seen this behavior? Does anyone know of a workaround for it? I have included a simple test form. Dump this form into a Visual Studio 2008 Smart Device application targeted at Windows Mobile 6 to see what I mean. Public Class frmTree Inherits System.Windows.Forms.Form #Region " Windows Form Designer generated code " Public Sub New() MyBase.new() ' This call is required by the Windows Form Designer. InitializeComponent() ' Add any initialization after the InitializeComponent() call. End Sub 'Form overrides dispose to clean up the component list. <System.Diagnostics.DebuggerNonUserCode()> _ Protected Overrides Sub Dispose(ByVal disposing As Boolean) If disposing AndAlso components IsNot Nothing Then components.Dispose() End If MyBase.Dispose(disposing) End Sub 'Required by the Windows Form Designer Private components As System.ComponentModel.IContainer Friend WithEvents TreeView1 As System.Windows.Forms.TreeView Private mainMenu1 As System.Windows.Forms.MainMenu 'NOTE: The following procedure is required by the Windows Form Designer 'It can be modified using the Windows Form Designer. 'Do not modify it using the code editor. <System.Diagnostics.DebuggerStepThrough()> _ Private Sub InitializeComponent() Dim TreeNode1 As System.Windows.Forms.TreeNode = New System.Windows.Forms.TreeNode("Node0") Dim TreeNode2 As System.Windows.Forms.TreeNode = New System.Windows.Forms.TreeNode("Node2") Dim TreeNode3 As System.Windows.Forms.TreeNode = New System.Windows.Forms.TreeNode("Node3") Dim TreeNode4 As System.Windows.Forms.TreeNode = New System.Windows.Forms.TreeNode("Node4") Dim TreeNode5 As System.Windows.Forms.TreeNode = New System.Windows.Forms.TreeNode("Node1") Dim TreeNode6 As System.Windows.Forms.TreeNode = New System.Windows.Forms.TreeNode("Node5") Dim TreeNode7 As System.Windows.Forms.TreeNode = New System.Windows.Forms.TreeNode("Node6") Dim TreeNode8 As System.Windows.Forms.TreeNode = New System.Windows.Forms.TreeNode("Node7") Me.mainMenu1 = New System.Windows.Forms.MainMenu Me.TreeView1 = New System.Windows.Forms.TreeView Me.SuspendLayout() ' 'TreeView1 ' Me.TreeView1.CheckBoxes = True Me.TreeView1.Location = New System.Drawing.Point(37, 41) Me.TreeView1.Name = "TreeView1" TreeNode2.Text = "Node2" TreeNode3.Text = "Node3" TreeNode4.Text = "Node4" TreeNode1.Nodes.AddRange(New System.Windows.Forms.TreeNode() {TreeNode2, TreeNode3, TreeNode4}) TreeNode1.Text = "Node0" TreeNode6.Text = "Node5" TreeNode7.Text = "Node6" TreeNode8.Text = "Node7" TreeNode5.Nodes.AddRange(New System.Windows.Forms.TreeNode() {TreeNode6, TreeNode7, TreeNode8}) TreeNode5.Text = "Node1" Me.TreeView1.Nodes.AddRange(New System.Windows.Forms.TreeNode() {TreeNode1, TreeNode5}) Me.TreeView1.Size = New System.Drawing.Size(171, 179) Me.TreeView1.TabIndex = 0 ' 'frmTree ' Me.AutoScaleDimensions = New System.Drawing.SizeF(96.0!, 96.0!) Me.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Dpi Me.AutoScroll = True Me.ClientSize = New System.Drawing.Size(240, 268) Me.Controls.Add(Me.TreeView1) Me.Menu = Me.mainMenu1 Me.Name = "frmTree" Me.Text = "frmTree" Me.ResumeLayout(False) End Sub #End Region End Class