diff --git a/htdocs/core/class/hookmanager.class.php b/htdocs/core/class/hookmanager.class.php
index 1f3f2ef3fcf..62611251280 100644
--- a/htdocs/core/class/hookmanager.class.php
+++ b/htdocs/core/class/hookmanager.class.php
@@ -105,7 +105,7 @@ class HookManager
 				if (in_array($context, $arrayhooks) || in_array('all', $arrayhooks))    // We instantiate action class only if initialized hook is handled by module
 				{
 					// Include actions class overwriting hooks
-					if (!is_object($this->hooks[$context][$module]))	// If set, class was already loaded
+					if (empty($this->hooks[$context][$module]) || !is_object($this->hooks[$context][$module]))	// If set to an object value, class was already loaded
 					{
 						$path = '/'.$module.'/class/';
 						$actionfile = 'actions_'.$module.'.class.php';
diff --git a/htdocs/main.inc.php b/htdocs/main.inc.php
index 7c72c6224de..9b85e62880a 100644
--- a/htdocs/main.inc.php
+++ b/htdocs/main.inc.php
@@ -232,6 +232,7 @@ if (!empty($conf->debugbar->enabled) && !GETPOST('dol_use_jmobile') && empty($_S
     include_once DOL_DOCUMENT_ROOT.'/debugbar/class/DebugBar.php';
     $debugbar = new DolibarrDebugBar();
     $renderer = $debugbar->getRenderer();
+    if (empty($conf->global->MAIN_HTML_HEADER)) $conf->global->MAIN_HTML_HEADER = '';
     $conf->global->MAIN_HTML_HEADER .= $renderer->renderHead();
 
     $debugbar['time']->startMeasure('pageaftermaster', 'Page generation (after environment init)');
@@ -886,7 +887,7 @@ if (empty($conf->global->MAIN_OPTIMIZEFORTEXTBROWSER) && !empty($user->conf->MAI
 }
 
 // set MAIN_OPTIMIZEFORCOLORBLIND for user
-$conf->global->MAIN_OPTIMIZEFORCOLORBLIND = $user->conf->MAIN_OPTIMIZEFORCOLORBLIND;
+$conf->global->MAIN_OPTIMIZEFORCOLORBLIND = empty($user->conf->MAIN_OPTIMIZEFORCOLORBLIND) ? '' : $user->conf->MAIN_OPTIMIZEFORCOLORBLIND;
 
 // Set terminal output option according to conf->browser.
 if (GETPOST('dol_hide_leftmenu', 'int') || !empty($_SESSION['dol_hide_leftmenu']))               $conf->dol_hide_leftmenu = 1;
@@ -1127,8 +1128,8 @@ function top_httphead($contenttype = 'text/html', $forcenocache = 0)
 		//	// A default security policy that keep usage of js external component like ckeditor, stripe, google, working
 		//	$contentsecuritypolicy = "font-src *; img-src *; style-src * 'unsafe-inline' 'unsafe-eval'; default-src 'self' *.stripe.com 'unsafe-inline' 'unsafe-eval'; script-src 'self' *.stripe.com 'unsafe-inline' 'unsafe-eval'; frame-src 'self' *.stripe.com; connect-src 'self';";
 		//}
-		//else $contentsecuritypolicy = $conf->global->MAIN_HTTP_CONTENT_SECURITY_POLICY;
-		$contentsecuritypolicy = $conf->global->MAIN_HTTP_CONTENT_SECURITY_POLICY;
+		//else
+		$contentsecuritypolicy = empty($conf->global->MAIN_HTTP_CONTENT_SECURITY_POLICY) ? '': $conf->global->MAIN_HTTP_CONTENT_SECURITY_POLICY;
 
 		if (!is_object($hookmanager)) $hookmanager = new HookManager($db);
 		$hookmanager->initHooks(array("main"));
diff --git a/htdocs/stripe/config.php b/htdocs/stripe/config.php
index 730203245f4..72fb593a305 100644
--- a/htdocs/stripe/config.php
+++ b/htdocs/stripe/config.php
@@ -34,12 +34,12 @@ global $stripearrayofkeysbyenv;
 
 $stripearrayofkeysbyenv = array(
 	0=>array(
-		"secret_key"      => $conf->global->STRIPE_TEST_SECRET_KEY,
-		"publishable_key" => $conf->global->STRIPE_TEST_PUBLISHABLE_KEY
+		"secret_key"      => empty($conf->global->STRIPE_TEST_SECRET_KEY) ? '' : $conf->global->STRIPE_TEST_SECRET_KEY,
+		"publishable_key" => empty($conf->global->STRIPE_TEST_PUBLISHABLE_KEY) ? '' : $conf->global->STRIPE_TEST_PUBLISHABLE_KEY
 	),
 	1=>array(
-		"secret_key"      => $conf->global->STRIPE_LIVE_SECRET_KEY,
-		"publishable_key" => $conf->global->STRIPE_LIVE_PUBLISHABLE_KEY
+		"secret_key"      => empty($conf->global->STRIPE_LIVE_SECRET_KEY) ? '' : $conf->global->STRIPE_LIVE_SECRET_KEY,
+		"publishable_key" => empty($conf->global->STRIPE_LIVE_PUBLISHABLE_KEY) ? '' : $conf->global->STRIPE_LIVE_PUBLISHABLE_KEY
 	)
 );
 
diff --git a/htdocs/theme/eldy/style.css.php b/htdocs/theme/eldy/style.css.php
index 526846f8a19..f9011f04e7a 100644
--- a/htdocs/theme/eldy/style.css.php
+++ b/htdocs/theme/eldy/style.css.php
@@ -237,7 +237,7 @@ print 'fontsizesmaller='.$fontsizesmaller."\n";
 print 'topMenuFontSize='.$topMenuFontSize."\n";
 print 'toolTipBgColor='.$toolTipBgColor."\n";
 print 'toolTipFontColor='.$toolTipFontColor."\n";
-print 'conf->global->THEME_SATURATE_RATIO='.$conf->global->THEME_SATURATE_RATIO." (must be between 0 and 1)\n";
+print 'conf->global->THEME_SATURATE_RATIO='.(empty($conf->global->THEME_SATURATE_RATIO) ? '' : $conf->global->THEME_SATURATE_RATIO)." (must be between 0 and 1)\n";
 print '*/'."\n";