diff --git a/htdocs/comm/action/card.php b/htdocs/comm/action/card.php
index 627c2f0ce51..4a00894d26b 100644
--- a/htdocs/comm/action/card.php
+++ b/htdocs/comm/action/card.php
@@ -76,11 +76,14 @@ if ($complete == 'na' || $complete == -2) {
 }
 
 if ($fulldayevent) {
-	$datep = dol_mktime('00', '00', 0, GETPOST("apmonth", 'int'), GETPOST("apday", 'int'), GETPOST("apyear", 'int'));
-	$datef = dol_mktime('23', '59', '59', GETPOST("p2month", 'int'), GETPOST("p2day", 'int'), GETPOST("p2year", 'int'));
+	$tzforfullday = getDolGlobalString('MAIN_STORE_FULL_EVENT_IN_GMT');
+	// For "full day" events, we must store date in GMT (It must be viewed as same moment everywhere)
+	$datep = dol_mktime('00', '00', 0, GETPOST("apmonth", 'int'), GETPOST("apday", 'int'), GETPOST("apyear", 'int'), $tzforfullday ? $tzforfullday : 'tzuserrel');
+	$datef = dol_mktime('23', '59', '59', GETPOST("p2month", 'int'), GETPOST("p2day", 'int'), GETPOST("p2year", 'int'), $tzforfullday ? $tzforfullday : 'tzuserrel');
+	//print $db->idate($datep); exit;
 } else {
-	$datep = dol_mktime($aphour, $apmin, 0, GETPOST("apmonth", 'int'), GETPOST("apday", 'int'), GETPOST("apyear", 'int'));
-	$datef = dol_mktime($p2hour, $p2min, '59', GETPOST("p2month", 'int'), GETPOST("p2day", 'int'), GETPOST("p2year", 'int'));
+	$datep = dol_mktime($aphour, $apmin, 0, GETPOST("apmonth", 'int'), GETPOST("apday", 'int'), GETPOST("apyear", 'int'), 'tzuserrel');
+	$datef = dol_mktime($p2hour, $p2min, '59', GETPOST("p2month", 'int'), GETPOST("p2day", 'int'), GETPOST("p2year", 'int'), 'tzuserrel');
 }
 
 // Security check
@@ -252,8 +255,15 @@ if (empty($reshook) && $action == 'add') {
 	$percentage = in_array(GETPOST('status'), array(-1, 100)) ? GETPOST('status') : (in_array($complete, array(-1, 100)) ? $complete : GETPOST("percentage", 'int')); // If status is -1 or 100, percentage is not defined and we must use status
 
 	// Clean parameters
-	$datep = dol_mktime($fulldayevent ? '00' : GETPOST("aphour", 'int'), $fulldayevent ? '00' : GETPOST("apmin", 'int'), $fulldayevent ? '00' : GETPOST("apsec", 'int'), GETPOST("apmonth", 'int'), GETPOST("apday", 'int'), GETPOST("apyear", 'int'), 'tzuser');
-	$datef = dol_mktime($fulldayevent ? '23' : GETPOST("p2hour", 'int'), $fulldayevent ? '59' : GETPOST("p2min", 'int'), $fulldayevent ? '59' : GETPOST("apsec", 'int'), GETPOST("p2month", 'int'), GETPOST("p2day", 'int'), GETPOST("p2year", 'int'), 'tzuser');
+	if ($fulldayevent) {
+		$tzforfullday = getDolGlobalString('MAIN_STORE_FULL_EVENT_IN_GMT');
+		// For "full day" events, we must store date in GMT (It must be viewed as same moment everywhere)
+		$datep = dol_mktime($fulldayevent ? '00' : GETPOST("aphour", 'int'), $fulldayevent ? '00' : GETPOST("apmin", 'int'), $fulldayevent ? '00' : GETPOST("apsec", 'int'), GETPOST("apmonth", 'int'), GETPOST("apday", 'int'), GETPOST("apyear", 'int'), $tzforfullday ? $tzforfullday : 'tzuser');
+		$datef = dol_mktime($fulldayevent ? '23' : GETPOST("p2hour", 'int'), $fulldayevent ? '59' : GETPOST("p2min", 'int'), $fulldayevent ? '59' : GETPOST("apsec", 'int'), GETPOST("p2month", 'int'), GETPOST("p2day", 'int'), GETPOST("p2year", 'int'), $tzforfullday ? $tzforfullday : 'tzuser');
+	} else {
+		$datep = dol_mktime($fulldayevent ? '00' : GETPOST("aphour", 'int'), $fulldayevent ? '00' : GETPOST("apmin", 'int'), $fulldayevent ? '00' : GETPOST("apsec", 'int'), GETPOST("apmonth", 'int'), GETPOST("apday", 'int'), GETPOST("apyear", 'int'), 'tzuser');
+		$datef = dol_mktime($fulldayevent ? '23' : GETPOST("p2hour", 'int'), $fulldayevent ? '59' : GETPOST("p2min", 'int'), $fulldayevent ? '59' : GETPOST("apsec", 'int'), GETPOST("p2month", 'int'), GETPOST("p2day", 'int'), GETPOST("p2year", 'int'), 'tzuser');
+	}
 
 	// Check parameters
 	if (!$datef && $percentage == 100) {
@@ -513,8 +523,16 @@ if (empty($reshook) && $action == 'update') {
 		$object->fetch_userassigned();
 		$object->oldcopy = clone $object;
 
-		$datep = dol_mktime($fulldayevent ? '00' : $aphour, $fulldayevent ? '00' : $apmin, 0, GETPOST("apmonth", 'int'), GETPOST("apday", 'int'), GETPOST("apyear", 'int'), 'tzuser');
-		$datef = dol_mktime($fulldayevent ? '23' : $p2hour, $fulldayevent ? '59' : $p2min, $fulldayevent ? '59' : '0', GETPOST("p2month", 'int'), GETPOST("p2day", 'int'), GETPOST("p2year", 'int'), 'tzuser');
+		// Clean parameters
+		if ($fulldayevent) {
+			$tzforfullday = getDolGlobalString('MAIN_STORE_FULL_EVENT_IN_GMT');
+			// For "full day" events, we must store date in GMT (It must be viewed as same moment everywhere)
+			$datep = dol_mktime($fulldayevent ? '00' : GETPOST("aphour", 'int'), $fulldayevent ? '00' : GETPOST("apmin", 'int'), $fulldayevent ? '00' : GETPOST("apsec", 'int'), GETPOST("apmonth", 'int'), GETPOST("apday", 'int'), GETPOST("apyear", 'int'), $tzforfullday ? $tzforfullday : 'tzuser');
+			$datef = dol_mktime($fulldayevent ? '23' : GETPOST("p2hour", 'int'), $fulldayevent ? '59' : GETPOST("p2min", 'int'), $fulldayevent ? '59' : GETPOST("apsec", 'int'), GETPOST("p2month", 'int'), GETPOST("p2day", 'int'), GETPOST("p2year", 'int'), $tzforfullday ? $tzforfullday : 'tzuser');
+		} else {
+			$datep = dol_mktime($fulldayevent ? '00' : GETPOST("aphour", 'int'), $fulldayevent ? '00' : GETPOST("apmin", 'int'), $fulldayevent ? '00' : GETPOST("apsec", 'int'), GETPOST("apmonth", 'int'), GETPOST("apday", 'int'), GETPOST("apyear", 'int'), 'tzuser');
+			$datef = dol_mktime($fulldayevent ? '23' : GETPOST("p2hour", 'int'), $fulldayevent ? '59' : GETPOST("p2min", 'int'), $fulldayevent ? '59' : GETPOST("apsec", 'int'), GETPOST("p2month", 'int'), GETPOST("p2day", 'int'), GETPOST("p2year", 'int'), 'tzuser');
+		}
 
 		$object->type_id     = dol_getIdFromCode($db, GETPOST("actioncode", 'aZ09'), 'c_actioncomm');
 		$object->label       = GETPOST("label", "alphanohtml");
@@ -1005,11 +1023,11 @@ if ($action == 'create') {
 
 	$datep = ($datep ? $datep : (is_null($object->datep) ? '' : $object->datep));
 	if (GETPOST('datep', 'int', 1)) {
-		$datep = dol_stringtotime(GETPOST('datep', 'int', 1), 0);
+		$datep = dol_stringtotime(GETPOST('datep', 'int', 1), 'tzuser');
 	}
 	$datef = ($datef ? $datef : $object->datef);
 	if (GETPOST('datef', 'int', 1)) {
-		$datef = dol_stringtotime(GETPOST('datef', 'int', 1), 0);
+		$datef = dol_stringtotime(GETPOST('datef', 'int', 1), 'tzuser');
 	}
 	if (empty($datef) && !empty($datep)) {
 		if (GETPOST("actioncode", 'aZ09') == 'AC_RDV' || empty($conf->global->AGENDA_USE_EVENT_TYPE_DEFAULT)) {
@@ -1024,16 +1042,16 @@ if ($action == 'create') {
 	print '<span id="dateend"'.(GETPOST("actioncode", 'aZ09') == 'AC_RDV' ? ' class="fieldrequired"' : '').'>'.$langs->trans("DateActionEnd").'</span>';
 	print '</td><td>';
 	if (GETPOST("afaire") == 1) {
-		print $form->selectDate($datep, 'ap', 1, 1, 0, "action", 1, 2, 0, 'fulldaystart'); // Empty value not allowed for start date and hours if "todo"
+		print $form->selectDate($datep, 'ap', 1, 1, 0, "action", 1, 2, 0, 'fulldaystart', '', '', '', 1, '', '', 'tzuserrel'); // Empty value not allowed for start date and hours if "todo"
 	} else {
-		print $form->selectDate($datep, 'ap', 1, 1, 1, "action", 1, 2, 0, 'fulldaystart');
+		print $form->selectDate($datep, 'ap', 1, 1, 1, "action", 1, 2, 0, 'fulldaystart', '', '', '', 1, '', '', 'tzuserrel');
 	}
 	print ' <span class="hideonsmartphone">&nbsp; &nbsp; - &nbsp; &nbsp;</span> ';
 	//print ' - ';
 	if (GETPOST("afaire") == 1) {
-		print $form->selectDate($datef, 'p2', 1, 1, 1, "action", 1, 0, 0, 'fulldayend');
+		print $form->selectDate($datef, 'p2', 1, 1, 1, "action", 1, 0, 0, 'fulldayend', '', '', '', 1, '', '', 'tzuserrel');
 	} else {
-		print $form->selectDate($datef, 'p2', 1, 1, 1, "action", 1, 0, 0, 'fulldayend');
+		print $form->selectDate($datef, 'p2', 1, 1, 1, "action", 1, 0, 0, 'fulldayend', '', '', '', 1, '', '', 'tzuserrel');
 	}
 	print '</td></tr>';
 
@@ -1518,20 +1536,21 @@ if ($id > 0) {
 
 		// Date start - end
 		print '<tr><td class="nowrap"><span class="fieldrequired">'.$langs->trans("DateActionStart").' - '.$langs->trans("DateActionEnd").'</span></td><td colspan="3">';
+		$tzforfullday = getDolGlobalString('MAIN_STORE_FULL_EVENT_IN_GMT');
 		if (GETPOST("afaire") == 1) {
-			print $form->selectDate($datep ? $datep : $object->datep, 'ap', 1, 1, 0, "action", 1, 1, 0, 'fulldaystart', '', '', '', 1, '', '', 'tzuser');
+			print $form->selectDate($datep ? $datep : $object->datep, 'ap', 1, 1, 0, "action", 1, 1, 0, 'fulldaystart', '', '', '', 1, '', '', $object->fulldayevent ? ($tzforfullday ? $tzforfullday : 'tzuser') : 'tzuser');
 		} elseif (GETPOST("afaire") == 2) {
-			print $form->selectDate($datep ? $datep : $object->datep, 'ap', 1, 1, 1, "action", 1, 1, 0, 'fulldaystart', '', '', '', 1, '', '', 'tzuser');
+			print $form->selectDate($datep ? $datep : $object->datep, 'ap', 1, 1, 1, "action", 1, 1, 0, 'fulldaystart', '', '', '', 1, '', '', $object->fulldayevent ? ($tzforfullday ? $tzforfullday : 'tzuser') : 'tzuser');
 		} else {
-			print $form->selectDate($datep ? $datep : $object->datep, 'ap', 1, 1, 1, "action", 1, 1, 0, 'fulldaystart', '', '', '', 1, '', '', 'tzuser');
+			print $form->selectDate($datep ? $datep : $object->datep, 'ap', 1, 1, 1, "action", 1, 1, 0, 'fulldaystart', '', '', '', 1, '', '', $object->fulldayevent ? ($tzforfullday ? $tzforfullday : 'tzuser') : 'tzuser');
 		}
 		print ' - ';
 		if (GETPOST("afaire") == 1) {
-			print $form->selectDate($datef ? $datef : $object->datef, 'p2', 1, 1, 1, "action", 1, 1, 0, 'fulldayend', '', '', '', 1, '', '', 'tzuser');
+			print $form->selectDate($datef ? $datef : $object->datef, 'p2', 1, 1, 1, "action", 1, 1, 0, 'fulldayend', '', '', '', 1, '', '', $object->fulldayevent ? ($tzforfullday ? $tzforfullday : 'tzuser') : 'tzuser');
 		} elseif (GETPOST("afaire") == 2) {
-			print $form->selectDate($datef ? $datef : $object->datef, 'p2', 1, 1, 1, "action", 1, 1, 0, 'fulldayend', '', '', '', 1, '', '', 'tzuser');
+			print $form->selectDate($datef ? $datef : $object->datef, 'p2', 1, 1, 1, "action", 1, 1, 0, 'fulldayend', '', '', '', 1, '', '', $object->fulldayevent ? ($tzforfullday ? $tzforfullday : 'tzuser') : 'tzuser');
 		} else {
-			print $form->selectDate($datef ? $datef : $object->datef, 'p2', 1, 1, 1, "action", 1, 1, 0, 'fulldayend', '', '', '', 1, '', '', 'tzuser');
+			print $form->selectDate($datef ? $datef : $object->datef, 'p2', 1, 1, 1, "action", 1, 1, 0, 'fulldayend', '', '', '', 1, '', '', $object->fulldayevent ? ($tzforfullday ? $tzforfullday : 'tzuser') : 'tzuser');
 		}
 		print '</td></tr>';
 
@@ -1972,7 +1991,8 @@ if ($id > 0) {
 		if (empty($object->fulldayevent)) {
 			print dol_print_date($object->datep, 'dayhour', 'tzuser');
 		} else {
-			print dol_print_date($object->datep, 'day', 'tzuser');
+			$tzforfullday = getDolGlobalString('MAIN_STORE_FULL_EVENT_IN_GMT');
+			print dol_print_date($object->datep, 'day', ($tzforfullday ? $tzforfullday : 'tzuser'));
 		}
 		if ($object->percentage == 0 && $object->datep && $object->datep < ($now - $delay_warning)) {
 			print img_warning($langs->trans("Late"));
@@ -1985,7 +2005,8 @@ if ($id > 0) {
 		if (empty($object->fulldayevent)) {
 			print dol_print_date($object->datef, 'dayhour', 'tzuser');
 		} else {
-			print dol_print_date($object->datef, 'day', 'tzuser');
+			$tzforfullday = getDolGlobalString('MAIN_STORE_FULL_EVENT_IN_GMT');
+			print dol_print_date($object->datef, 'day', ($tzforfullday ? $tzforfullday : 'tzuser'));
 		}
 		if ($object->percentage > 0 && $object->percentage < 100 && $object->datef && $object->datef < ($now - $delay_warning)) {
 			print img_warning($langs->trans("Late"));
diff --git a/htdocs/comm/action/document.php b/htdocs/comm/action/document.php
index c69d396cf26..3de00e9cb6f 100644
--- a/htdocs/comm/action/document.php
+++ b/htdocs/comm/action/document.php
@@ -201,7 +201,8 @@ if ($object->id > 0) {
 	if (empty($object->fulldayevent)) {
 		print dol_print_date($object->datep, 'dayhour', 'tzuser');
 	} else {
-		print dol_print_date($object->datep, 'day', 'tzuser');
+		$tzforfullday = getDolGlobalString('MAIN_STORE_FULL_EVENT_IN_GMT');
+		print dol_print_date($object->datep, 'day', ($tzforfullday ? $tzforfullday : 'tzuser'));
 	}
 	if ($object->percentage == 0 && $object->datep && $object->datep < ($now - $delay_warning)) {
 		print img_warning($langs->trans("Late"));
@@ -214,7 +215,8 @@ if ($object->id > 0) {
 	if (empty($object->fulldayevent)) {
 		print dol_print_date($object->datef, 'dayhour', 'tzuser');
 	} else {
-		print dol_print_date($object->datef, 'day', 'tzuser');
+		$tzforfullday = getDolGlobalString('MAIN_STORE_FULL_EVENT_IN_GMT');
+		print dol_print_date($object->datef, 'day', ($tzforfullday ? $tzforfullday : 'tzuser'));
 	}
 	if ($object->percentage > 0 && $object->percentage < 100 && $object->datef && $object->datef < ($now - $delay_warning)) {
 		print img_warning($langs->trans("Late"));
diff --git a/htdocs/comm/action/index.php b/htdocs/comm/action/index.php
index 72e50d9292d..81df122f1a9 100644
--- a/htdocs/comm/action/index.php
+++ b/htdocs/comm/action/index.php
@@ -545,7 +545,8 @@ if ($user->rights->agenda->myactions->create || $user->rights->agenda->allaction
 	$newparam .= '&month='.((int) $month).'&year='.((int) $tmpforcreatebutton['year']).'&mode='.urlencode($mode);
 
 	//$param='month='.$monthshown.'&year='.$year;
-	$hourminsec = '100000';
+	$hourminsec = dol_print_date(dol_mktime(10, 0, 0, 1, 1, 1970, 'gmt'), '%H', 'gmt').'0000';	// Set $hourminsec to '100000' to auto set hour to 10:00 at creation
+
 	$newcardbutton .= dolGetButtonTitle($langs->trans("AddAction"), '', 'fa fa-plus-circle', DOL_URL_ROOT.'/comm/action/card.php?action=create&datep='.sprintf("%04d%02d%02d", $tmpforcreatebutton['year'], $tmpforcreatebutton['mon'], $tmpforcreatebutton['mday']).$hourminsec.'&backtopage='.urlencode($_SERVER["PHP_SELF"].($newparam ? '?'.$newparam : '')));
 }
 
@@ -812,17 +813,17 @@ if ($resql) {
 
 		// event->datep and event->datef must be GMT date.
 		if ($event->fulldayevent) {
-			// TODO...
-			$event->datep = $db->jdate($obj->datep);
-			$event->datef = $db->jdate($obj->datep2);
+			$tzforfullday = getDolGlobalString('MAIN_STORE_FULL_EVENT_IN_GMT');
+			$event->datep = $db->jdate($obj->datep, $tzforfullday ? 'tzuser' : 'tzserver');	// If saved in $tzforfullday = gmt, we must invert date to be in user tz
+			$event->datef = $db->jdate($obj->datep2, $tzforfullday ? 'tzuser' : 'tzserver');
 		} else {
 			// Example: $obj->datep = '1970-01-01 01:00:00', jdate will return 0 if TZ of PHP server is Europe/Berlin (+1)
-			$event->datep = $db->jdate($obj->datep);
-			$event->datef = $db->jdate($obj->datep2);
+			$event->datep = $db->jdate($obj->datep, 'tzserver');
+			$event->datef = $db->jdate($obj->datep2, 'tzserver');
 		}
 		//$event->datep_formated_gmt = dol_print_date($event->datep, 'dayhour', 'gmt');
-		//var_dump($obj->datep);
-		//var_dump($event->datep);
+		//var_dump($obj->id.' '.$obj->datep.' '.dol_print_date($obj->datep, 'dayhour', 'gmt'));
+		//var_dump($obj->id.' '.$event->datep.' '.dol_print_date($event->datep, 'dayhour', 'gmt'));
 
 		$event->type_code = $obj->type_code;
 		$event->type_label = $obj->type_label;
diff --git a/htdocs/comm/action/list.php b/htdocs/comm/action/list.php
index de961b5517e..e2b412e15db 100644
--- a/htdocs/comm/action/list.php
+++ b/htdocs/comm/action/list.php
@@ -693,7 +693,7 @@ $tmpforcreatebutton = dol_getdate(dol_now(), true);
 $newparam = '&month='.str_pad($month, 2, "0", STR_PAD_LEFT).'&year='.$tmpforcreatebutton['year'];
 
 //$param='month='.$monthshown.'&year='.$year;
-$hourminsec = '100000';
+$hourminsec = dol_print_date(dol_mktime(10, 0, 0, 1, 1, 1970, 'gmt'), '%H', 'gmt').'0000';	// Set $hourminsec to '100000' to auto set hour to 10:00 at creation
 
 $url = DOL_URL_ROOT.'/comm/action/card.php?action=create';
 $url .= '&datep='.sprintf("%04d%02d%02d", $tmpforcreatebutton['year'], $tmpforcreatebutton['mon'], $tmpforcreatebutton['mday']).$hourminsec;
@@ -953,7 +953,12 @@ while ($i < min($num, $limit)) {
 	// Start date
 	if (!empty($arrayfields['a.datep']['checked'])) {
 		print '<td class="center nowraponall">';
-		print dol_print_date($db->jdate($obj->dp), $formatToUse, 'tzuser');
+		if (empty($obj->fulldayevent)) {
+			print dol_print_date($db->jdate($obj->dp), $formatToUse, 'tzuser');
+		} else {
+			$tzforfullday = getDolGlobalString('MAIN_STORE_FULL_EVENT_IN_GMT');
+			print dol_print_date($db->jdate($obj->dp), $formatToUse, ($tzforfullday ? $tzforfullday : 'tzuser'));
+		}
 		$late = 0;
 		if ($actionstatic->hasDelay() && $actionstatic->percentage >= 0 && $actionstatic->percentage < 100 ) {
 			$late = 1;
@@ -967,7 +972,12 @@ while ($i < min($num, $limit)) {
 	// End date
 	if (!empty($arrayfields['a.datep2']['checked'])) {
 		print '<td class="center nowraponall">';
-		print dol_print_date($db->jdate($obj->dp2), $formatToUse, 'tzuser');
+		if (empty($obj->fulldayevent)) {
+			print dol_print_date($db->jdate($obj->dp2), $formatToUse, 'tzuser');
+		} else {
+			$tzforfullday = getDolGlobalString('MAIN_STORE_FULL_EVENT_IN_GMT');
+			print dol_print_date($db->jdate($obj->dp2), $formatToUse, ($tzforfullday ? $tzforfullday : 'tzuser'));
+		}
 		print '</td>';
 	}
 
diff --git a/htdocs/resource/element_resource.php b/htdocs/resource/element_resource.php
index d0ca6416390..068dba8c50a 100644
--- a/htdocs/resource/element_resource.php
+++ b/htdocs/resource/element_resource.php
@@ -383,7 +383,8 @@ if (!$ret) {
 			if (empty($act->fulldayevent)) {
 				print dol_print_date($act->datep, 'dayhour', 'tzuser');
 			} else {
-				print dol_print_date($act->datep, 'day', 'tzuser');
+				$tzforfullday = getDolGlobalString('MAIN_STORE_FULL_EVENT_IN_GMT');
+				print dol_print_date($act->datep, 'day', ($tzforfullday ? $tzforfullday : 'tzuser'));
 			}
 			if ($act->percentage == 0 && $act->datep && $act->datep < ($now - $delay_warning)) {
 				print img_warning($langs->trans("Late"));
@@ -396,7 +397,8 @@ if (!$ret) {
 			if (empty($act->fulldayevent)) {
 				print dol_print_date($act->datef, 'dayhour', 'tzuser');
 			} else {
-				print dol_print_date($act->datef, 'day', 'tzuser');
+				$tzforfullday = getDolGlobalString('MAIN_STORE_FULL_EVENT_IN_GMT');
+				print dol_print_date($act->datef, 'day', ($tzforfullday ? $tzforfullday : 'tzuser'));
 			}
 			if ($act->percentage > 0 && $act->percentage < 100 && $act->datef && $act->datef < ($now - $delay_warning)) {
 				print img_warning($langs->trans("Late"));