Event not firing after item updated, even after re-adding the handler - wpf

Question

In my Program Cyrus-Beck algorithm, I have to clip the points. The points inside the clipping window have to be red. The outside is still black.
I represent point in program as rectangle and I give the event handler for delete the point. when I wanted to delete points, points outside the window is working, but points that inside polygon didn't work, event the right-click event not call.
Here is my Point class.
Ignore the Component class, because it just nothing than handler to canvas in the main window
Public Class Points
Inherits Component
Public items As List(Of Point) = New List(Of Point)()
Public rects As List(Of Rectangle) = New List(Of Rectangle)
'add element
Public Overrides Sub Canvas1_MouseMove(sender As Object, e As MouseEventArgs)
canvas.Cursor = Cursors.Pen
End Sub
Public Overrides Sub Canvas1_MouseDown(sender As Object, e As MouseButtonEventArgs)
canvas.Cursor = Cursors.Pen
If e.LeftButton = MouseButtonState.Pressed Then
items.Add(e.GetPosition(canvas))
Dim p As Rectangle = New Rectangle()
p.Width = 3
p.Height = 3
canvas.SetLeft(p, e.GetPosition(canvas).X)
canvas.SetTop(p, e.GetPosition(canvas).Y)
p.Stroke = Brushes.Black
p.Fill = Brushes.Black
rects.Add(p)
End If
End Sub
'deleting element
'this method not calling when the element has updated
Sub point_rightClick(sender As Object, e As MouseButtonEventArgs)
Dim temp As Rectangle = New Rectangle()
temp = DirectCast(sender, Rectangle)
Dim pt As Point = New Point(Controls.Canvas.GetLeft(temp), Controls.Canvas.GetTop(temp))
canvas.Children.Remove(temp)
items.Remove(pt)
rects.Remove(temp)
End Sub
Public Shared Function samePoint(one As Rectangle, two As Rectangle) As Boolean
Return ((Controls.Canvas.GetLeft(one) = Controls.Canvas.GetLeft(two)) And (Controls.Canvas.GetTop(one) = Controls.Canvas.GetTop(two)))
End Function
Public Shared Function samePoint(one As Point, two As Rectangle) As Boolean
Return (one.X = Controls.Canvas.GetLeft(two)) And (one.Y = Controls.Canvas.GetTop(two))
End Function
End Class
To able to delete, I have deleting that represents the status, if deleting is true and currentState = MouseState.Pointer. the code will add handler to all the points (rectangles).
Private Sub chge_pointer_Click(sender As Object, e As RoutedEventArgs) Handles chge_pointer.Click
currentState = MouseState.Pointer
deleting = True
chooseHandler()
End Sub
Private Sub chooseHandler()
If deleting Then
For Each r As Rectangle In points.rects
AddHandler r.MouseRightButtonDown, AddressOf points.point_rightClick
Next
Else
For Each r As Rectangle In points.rects
RemoveHandler r.MouseRightButtonDown, AddressOf points.point_rightClick
Next
End If
End Sub
Before I modified the points to be red, I have to have a loop to check if the position is same, if the position same so edit the points
Dim z As CyrusBeck = New CyrusBeck(clippingWindow)
z.Clip(points.items)
'CyrusBeck has a properties 'points'
'CyrusBeck.points saves the all the point that inside the clipping window
For i As Integer = 0 To points.rects.Count - 1
For Each p As Point In z.points
If CGAProject.Points.samePoint(p, points.rects.Item(i)) Then
Dim temp_r As Rectangle = New Rectangle()
temp_r = points.rects.Item(i)
temp_r.Stroke = Brushes.Red
temp_r.Fill = Brushes.Red
points.rects.Add(temp_r)
points.rects.RemoveAt(i)
End If
Next
Next
when the program reaches this, currentState would Never to be MouseState.Pointer. so if user want to delete a point, user have to be press button chge_pointer so my chge_pointer_Click is called and all my handler would be re-setted again.
Why Rectangle.MouseRightButtonDown is not call when the rectangle has updated?
the rectangles that haven't update call the Rectangle.MouseRightButtonDown event, so I have re-set the handler.
What's worng?
Is there any alternative way so user can delete rectangle inside and outside the window?
Note :
I have resetted the handler just after I assigned back my Rectangle to the list, but it still didn't work.
I also create AddHandler temp_r.MouseRightButtonDown, AddressOf points.point_rightClick just after I assigned back my Rectangle to the list, but it didn't work either.

Answer 1

At the end of your events for clicking, like:
Sub point_rightClick(sender As Object, e As MouseButtonEventArgs)
I think you should have a "handles".
E.g.
Sub point_rightClick(sender As Object, e As MouseButtonEventArgs) Handles point.MouseClick
Without this, the sub will never be called (as it seems is happening).
This method also has no "handles"
Public Overrides Sub Canvas1_MouseDown(sender As Object, e As MouseButtonEventArgs)
and it could be:
Public Overrides Sub Canvas1_MouseDown(sender As Object, e As MouseButtonEventArgs) Handles Canvas1.MouseDown