Hello,
In the plugin "hikashop/vendorlocationfilter", please replace
$filter_mode = $this->params->get('filter_mode', 'zip;city');
By
if($empty_is_all && empty($location_search))
return;
$filter_mode = $this->params->get('filter_mode', 'zip;city');
So we will skip all the rest of the process if we are sure that there is no search and the setting "empty is *all*" is active.
Regarding the dropdown, the best is to override the view for the module "mod_market_locationsearch / default".
The idea is to replace the input box by a dropdown containing all the cities you want to make available.
The HTML field need to keep the same "name".
<input name="location_search" type="text" value="<?php echo $location_search; ?>" id="hikamarket_vendor_locationsearch_input" placeholder="<?php echo @$params->get('placeholder'); ?>" />
You can use the Joomla JHTML system to help you with the display.
Regards,