Happened if there were not any searchtags already present in the query.
// Check if this tag is already in the search query and ignore it if it is.
// Each tag is always separated by a space
- $current_tags = explode(' ', $params['searchtags']);
+ if (isset($params['searchtags'])) {
+ $current_tags = explode(' ', $params['searchtags']);
+ } else {
+ $current_tags = array();
+ }
$addtag = true;
foreach ($current_tags as $value) {
if ($value === $_GET['addtag']) {