What happens after Form.Close? <p>I have a code like</p> <pre><code>void onDgvRelations_CellMouseClick(object sender, DataGridViewCellMouseEventArgs e) { if (e.ColumnIndex == 2 &amp;&amp; ktlg == null) { this.Cursor = Cursors.WaitCursor; ktlg = new FormKatalog(); ktlg.Show(); this.Cursor = Cursors.Default; } } </code></pre> <p>The idea is to check if a form </p> <blockquote> <p>FormKatalog ktlg</p> </blockquote> <p>is closed. If it's closed I have to create a new form and show it to user. The problem is that after user close the form, variable ktlg will never be null.</p> <p>How to check properly if a form was not instantiated OR was closed by user?</p>