title: Hide and show ttk.Combobox dropdown list
body: <p><strong>Situation:</strong> When I use the mouse button to click the "down-arrow" of a <code>ttk.Combobox</code> it's standard behaviour is to show a dropdown list. When the down arrow is clicked on the second time, the combobox dropdown list will become hidden.</p>
  
  <p>Using the keyboard. it is possible to show the combobox dropdown list by pressing the "down-arrow" once. Pressing the "down-arrow" further will scroll down the dropdown list to its end. Pressing the "up-arrow" repeatedly will scroll up the dropdown list until the highlight/selection reaches to the top of the dropdown list, but it does not finally hide the dropdown list.     </p>
  
  <p><strong>Question:</strong> Without using the mouse or keyboard, that is, using computer programming, how can I hide an expose dropdown list of a <code>ttk.Combobox</code>. I am aware that the <em><code>w.event_generate("&lt;Down&gt;")</code></em> command can be used to program a <code>ttk.Combobox</code> to show it's dropdown list. But how do I achieve the opposite? That is, how can I use the same <em>w.event_generate()</em> command to hide the dropdown list? Or what other tkinter command should I use to achieve what I want?</p>