enableFilteringMode on empty input

Is there a way to make an “enableFilteringMode” combo with partial load, to do a request with an empty mask to load (and display) dinamically the contents when the input is empty?
Also, when cache is disabled and auto-subloading enabled, when reaching the last element in the combo list, the browser keeps making one request after another even if the answers are empty. can this be avoided?

Please, try to use attached file istead of the original one. If the issue still occurs, please provide the sample or direct link to the problematic page.
dhtmlxcombo.zip (9.52 KB)