title: Trying to combine two arrays doesn't work
body: <p>I am trying to combine two select boxes into one. Here's the code:</p>
  
  <pre><code>//Selectbox 1
  &lt;?php $aCities = City::newInstance()-&gt;listAll(); ?&gt;
  &lt;?php if(count($aCities) &gt; 0 ) { ?&gt;
      &lt;select id="dropdowncities"&gt;
          &lt;option value=""&gt;&lt;?php _e('Select your location...')?&gt;&lt;/option&gt;
          &lt;?php foreach($aCities as $city) { ?&gt;
              &lt;option value="&lt;?php echo $city['s_name'] ; ?&gt;"&gt;&lt;?php echo $city['s_name'] ; ?&gt;
              &lt;/option&gt;
          &lt;?php } ?&gt;
      &lt;/select&gt;
  &lt;?php } ?&gt;
  
  
  //Selectbox 2
  &lt;?php $aRegions = Region::newInstance()-&gt;listAll(); ?&gt;
  &lt;?php if(count($aRegions) &gt; 0 ) { ?&gt;
      &lt;select id="dropdownregions"&gt;
          &lt;option value=""&gt;&lt;?php _e('Select your Region...')?&gt;&lt;/option&gt;
          &lt;?php foreach($aRegions as $region) { ?&gt;
              &lt;option value="&lt;?php echo $region['s_name'] ; ?&gt;"&gt;&lt;/option&gt;
          &lt;?php } ?&gt;
      &lt;/select&gt;
  &lt;?php } ?&gt;
  </code></pre>
  
  <p>As it is now both select boxes work fine and i get the correct results/values in them. But when i try to combine them into one single select box, like at the code below i get no results at all:</p>
  
  <pre><code>//Combine two select boxes
  &lt;?php $aRegions = Region::newInstance()-&gt;listAll(); ?&gt;
  &lt;?php $aCities = City::newInstance()-&gt;listAll(); ?&gt;
  &lt;?php $cityandregion = array_combine($aRegions, $aCities); ?&gt;
  &lt;?php if(count($aCities) &gt; 0 ) { ?&gt;
      &lt;select id="dropdowncitiesregions"&gt;
          &lt;option value=""&gt;&lt;?php _e('Select your city and region...')?&gt;&lt;/option&gt;
          &lt;?php foreach($cityandregion as $city=&gt;$region) { ?&gt;
              &lt;option value="&lt;?php echo $city['s_name'] ; ?&gt;&lt;?php echo $region['s_name'] ; ?&gt;"&gt;&lt;?php echo $cityandregion['s_name'] ; ?&gt;&lt;/option&gt;
          &lt;?php } ?&gt;
      &lt;/select&gt;
  &lt;?php } ?&gt;
  </code></pre>
  
  <p>What i 'm doing wrong? </p>
  
  <p>UPDATE:i get this message in debug file-> "PHP Warning: array_combine(): Both parameters should have an equal number of elements"</p>