executing MouseDown then executing KeyUp (Object sender cant keep track the latest object)

Question

Hi,

I have some question to ask because I don't understand why is it happening like that.

I have 2 polygon created and displayed.
I've make mouseDown, mouseUp, mouseMove event. (For some movement for the polygon)
Now i wanted to implement keyUp(pressing delete button from keyboard, then delete the polygon)

This is the code for MouseUp:

private void Shape_MouseUp(object sender, MouseEventArgs e)
      {
         isDraggingA = false;
         controlALL = (Control)sender;

         if (e.Button == MouseButtons.Left)
         {
            OB = sender;
            controlALL.KeyUp += new KeyEventHandler(DeleteButton);
           
         }
      }

the " object sender " is to identify which polygon I've selected
then, I've made "Shape_MouseUp" it so that it will run "DeleteButton" function

Below is my DeleteButton code:

private void DeleteButton(object sender, KeyEventArgs e)
      {

         controlALL = (Control)OB;

         if (e.KeyCode == Keys.Delete)
         {
            controlALL.Dispose();
         }

        
      }

PROBLEM : When i execute this 2 code, the result i got is,

when i click on polygon 1, then press 'delete'    SUCCESS
But when i click on polygon 2, then press 'delete' NOTHING HAPPEN

 

I don't know why the function "DeleteButton(object sender, KeyEventArgs e) cannot get the polygon 2.
Any idea?