It is still happen in the sample.
The problem doesn't occur with the code
Dim Image1 As New System.Web.UI.WebControls.Image()
Image1.ToolTip = "Insert today's date"
Image1.ImageUrl = "tools.gif"
Image1.CssClass = "CuteEditorButton"
SetMouseEvents(Image1)
Image1.Attributes("onclick")="Testing();"
tc.Control.Controls.Add(Image1)
But it will be a problem with this
Dim ctrlTwoColumns As System.Web.UI.WebControls.WebControl
ctrlTwoColumns = Editor1.CreateCommandButton("Testing", "download.gif", "Testing")
ctrlTwoColumns.Attributes("onclick") = "Testing();"
tc.Control.Controls.Add(ctrlTwoColumns)
Maybe something wrong with System.Web.UI.WebControls.WebControl when receiving doubleclik event