Thanks, I tried that code but I got this error message:
AJAX Error
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<b>Warning</b>: Illegal string offset 'posts_per_page' in <b>/wp-content/plugins/mappress-google-maps-for-wordpress/pro/mappress_query.php</b> on line <b>83</b><br />
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<b>Warning</b>: Illegal string offset 'map' in <b>/wp-content/plugins/mappress-google-maps-for-wordpress/pro/mappress_query.php</b> on line <b>110</b><br />
<br />
<b>Warning</b>: Illegal string offset 'post_type' in <b>/wp-content/plugins/mappress-google-maps-for-wordpress/pro/mappress_query.php</b> on line <b>111</b><br />
<br />
<b>Warning</b>: Illegal string offset 'cache_results' in <b>/wp-content/plugins/mappress-google-maps-for-wordpress/pro/mappress_query.php</b> on line <b>112</b><br />