First, add a class level variable to store the button that was clicked (i.e. the one to be removed from the tool strip.
Dim clickedButton As ToolStripItem = Nothing
Then add the following code to the Opening event of your context menu. This code attempts to identify the button that was clicked when the prior to the context menu being displayed:
Private Sub ContextMenuStrip1_Opening(sender As Object, e As System.ComponentModel.CancelEventArgs) Handles ContextMenuStrip1.Opening
Dim strip As ToolStrip = TryCast(ContextMenuStrip1.SourceControl, ToolStrip)
clickedButton = Nothing
If strip IsNot Nothing Then
Dim position As Point = strip.PointToClient(MousePosition)
For Each item As ToolStripItem In strip.Items
If item.Bounds.Contains(position) Then clickedButton = item
Next
End If
End Sub</pre>
Finally, in your remove menu item, add the following code to remove the actual button:
<pre>
Private Sub RemoveToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles RemoveToolStripMenuItem.Click
If clickedButton IsNot Nothing Then ToolStrip1.Items.Remove(clickedButton)
End Sub