title: Extjs combobox: hide selected value from dropdown list
body: <p>I'm using ExtJS 4 and looking for a way I can hide currently selected value from combo's dropdown list?</p>
  
  <p>So instead of this ("Alaska" currently selected in combobox):</p>
  
  <p><img src="https://i.stack.imgur.com/0H6vp.png" alt="default combobox behaviour"></p>
  
  <p>I want the list of values look like this:</p>
  
  <p><img src="https://i.stack.imgur.com/OMhFN.png" alt="enter image description here"></p>
  
  <p>In my case the combobox is <em>not editable</em> (i.e. you can't input an arbitrary value), I don't think it makes much sense to display the selected value two times: once in the input field and once in the dropdown list. I already see what is selected, I want the dropdown list to only show me <strong>other</strong> options I can select.</p>
  
  <p>So far I don't see an easy way to do it. Probably the best place to start at is filtering combobox store but combobox uses its own filters for live search functionality.</p>
  
  <p>Anybody considered this problem? Am I trying to do something weird? 
  I'm surprised that I haven't been able to find any related topics.</p>