Control Focus Events Cycle
When you change the focus by using the keyboard (TAB, SHIFT+TAB, and so on), by calling the Select or SelectNextControl methods, or by setting the ContainerControl.ActiveControl property to the current form, focus events occur in the following order:
Private Sub DataGridView1_Leave(ByVal sender As Object, ByVal e As System.EventArgs) Handles DataGridView1.Leave
Private Sub DataGridView1_LostFocus(ByVal sender As Object, ByVal e As System.EventArgs) Handles DataGridView1.LostFocus
When you change the focus by using the mouse or by calling the Focus method, focus events occur in the following order:
If the CausesValidation property is set to false, the Validating and Validated events are suppressed.
The Enter and Leave events are suppressed by the Form class. The equivalent events in the Form class are the Activated and Deactivate events. The Enter and Leave events are hierarchical and will cascade up and down the parent chain until the appropriate control is reached. For example, assume you have a Form with two GroupBox controls, and each GroupBox control has one TextBox control. When the caret is moved from one TextBox to the other, the Leave event is raised for the TextBox and GroupBox, and the Enter event is raised for the other GroupBox and TextBox.