Nice! Didn't know about that, I guess from the context of keeping it all within that same SP and that same search area, it's not possible. Which is what most people want however, this is a good alternative.

Thanks so much but we tried that but we had some issues by enabling that plugin , so do you have any idea can we include another knowledge base in the search source ?

(function(query) {
var results = [];
//Here goes the logic. Compute results however you want!
var kb = new GlideRecord('kb_knowledge');
kb.addQuery('workflow_state', 'published');
kb.addQuery('valid_to', '>=', (new GlideDate()).getLocalDate().getValue());
kb.addQuery('kb_knowledge_base', $sp.getValue('kb_knowledge_base'));
kb.addQuery('123TEXTQUERY321', query);
kb.setLimit(data.limit);
kb.query();
data.article_count = kb.getRowCount();

var kbCount = 0;
while (kb.next() && kbCount < data.limit) {
// Does user have permission to see this item?
if (!$sp.canReadRecord("kb_knowledge", kb.getUniqueValue()))
continue;

var article = {};
$sp.getRecordDisplayValues(article, kb, 'sys_id,number,short_description,published,text');
article.publishedUTC = kb.getValue('published');
article.type = "kb";
if (!article.text)
article.text = "";
article.text = $sp.stripHTML(article.text) + "";
article.text = article.text.substring(0, 200);
article.score = parseInt(kb.ir_query_score.getDisplayValue());
article.label = article.short_description;
article.primary = article.short_description;
results.push(article);
kbCount++;
}
$sp.logSearch('kb_knowledge', data.q, kb.getRowCount());

return results;
})(query);