title: Get event to run when Input in empty
body: <p>I want an event to run when I type in the input, that works.
  But only when I <em>type</em> something, not when the field is empty, I want that too</p>
  <p>Here's a little template code I wrote that resembles my issue</p>
  <pre><code>import PySimpleGUI as sg
  
  list1 = ['a', 'b', 'c']
  matches = []
  out = []
  
  
  
  layout = [
  [sg.InputText('', key='-search-', change_submits=True)],
  [sg.Listbox(values=out, key='-list-', size=(10,10))]  
  ]
  
  
  
  
  window = sg.Window('Search', layout, size=(300, 300))
  
  
  
  while True:
    event, values = window.read()
  
    if values['-search-']:
      SearchTerm = values['-search-']
      SearchTerm.replace(&quot;['&quot;, &quot;&quot;)
      SearchTerm.replace(&quot;']&quot;, &quot;&quot;)
      print(&quot;Search Term = &quot; + SearchTerm)
  
      if SearchTerm == &quot;&quot;:
        out = list1
        window.Element('-list-').Update(values=list1)
          
      if SearchTerm != &quot;&quot;:
        for i in list1:
          if SearchTerm in i:
            if i not in matches:
              matches.append(i)
              outlist = matches
              window.Element('-list-').Update(values=outlist)
  
    if event == sg.WIN_CLOSED or event == 'Exit':
        break
  </code></pre>