title: RadComboBox with Checkbox enabled - Persists last selected item text
body: <p>I have developed a user control which has only a RadComboBox with checkbox enabled in it. The problem that I am facing in my pages is, whenever I deselect all the checkbox items with in the RadComboBox and on close of it, the last selected item is displayed in its text section. I am not finding a way to fix it. </p>
  
  <p>In the ideal scenario, if nothing / everything is selected, I am defaulting to the text "All". If any item is selected, the item text is displayed. Can some one help me, if I have to do any specific check to fix this problem?</p>
  
  <p>I am sharing a animated GIF for my issue below.</p>
  
  <p><img src="https://i.stack.imgur.com/tQcHT.gif" alt="enter image description here"></p>
  
  <p>Thanks,
  Sriram</p>