diff --git a/htdocs/core/class/lessc.class.php b/htdocs/core/class/lessc.class.php
index 1d581a07e7f..cb6caf838e2 100644
--- a/htdocs/core/class/lessc.class.php
+++ b/htdocs/core/class/lessc.class.php
@@ -3212,7 +3212,7 @@ class lessc_parser
 		$value = null;
 		if ($this->literal("(") &&
 			$this->keyword($feature) &&
-			($this->literal(":") && $this->expression($value) || true) &&
+			($this->literal(":") && $this->expression($value)) &&
 			$this->literal(")")
 			) {
 				$out = array("mediaExp", $feature);
diff --git a/htdocs/core/db/DoliDB.class.php b/htdocs/core/db/DoliDB.class.php
index e2659e224a4..0c62be0a85a 100644
--- a/htdocs/core/db/DoliDB.class.php
+++ b/htdocs/core/db/DoliDB.class.php
@@ -29,7 +29,7 @@ require_once DOL_DOCUMENT_ROOT.'/core/db/Database.interface.php';
  */
 abstract class DoliDB implements Database
 {
-	/** @var bool|resource|SQLite3|PgSql\connection Database handler */
+	/** @var bool|resource|mysqli|SQLite3|PgSql\connection Database handler */
 	public $db;
 	/** @var string Database type */
 	public $type;
@@ -37,8 +37,10 @@ abstract class DoliDB implements Database
 	public $forcecharset = 'utf8';
 	/** @var string Collate used to force collate when creating database */
 	public $forcecollate = 'utf8_unicode_ci';
+
 	/** @var resource Resultset of last query */
 	private $_results;
+
 	/** @var bool true if connected, else false */
 	public $connected;
 	/** @var bool true if database selected, else false */
@@ -73,7 +75,8 @@ abstract class DoliDB implements Database
 
 
 	/**
-	 *	Return the DB prefix
+	 *	Return the DB prefix found into prefix_db (if it was set manually by doing $db->prefix_db=...).
+	 *  Otherwise return MAIN_DB_PREFIX (common use).
 	 *
 	 *	@return string		The DB prefix
 	 */
diff --git a/htdocs/core/db/mysqli.class.php b/htdocs/core/db/mysqli.class.php
index 7d184dc06cf..d34aca48ed9 100644
--- a/htdocs/core/db/mysqli.class.php
+++ b/htdocs/core/db/mysqli.class.php
@@ -36,10 +36,12 @@ class DoliDBMysqli extends DoliDB
 	public $db;
 	//! Database type
 	public $type = 'mysqli';
+
 	//! Database label
 	const LABEL = 'MySQL or MariaDB';
 	//! Version min database
 	const VERSIONMIN = '5.0.3';
+
 	/** @var bool|mysqli_result Resultset of last query */
 	private $_results;