Invert PROJECT_HIDE_PROJECT_LIST_ON_PROJECT_AREA into

PROJECT_SHOW_OPEN_PROJECTS_LIST_ON_PROJECT_AREA

htdocs/projet/index.php

@@ -412,10 +412,9 @@ if ($resql) {
 	dol_print_error($db);
 }
 
-if (empty($conf->global->PROJECT_HIDE_PROJECT_LIST_ON_PROJECT_AREA)) {
-	// This list can be very long, so we allow to hide it to prefer to use the list page.
-	// Add constant PROJECT_HIDE_PROJECT_LIST_ON_PROJECT_AREA to hide this list
-
+if (!getDolGlobalInt('PROJECT_USE_OPPORTUNITIES') || getDolGlobalInt('PROJECT_SHOW_OPEN_PROJECTS_LIST_ON_PROJECT_AREA')) {
+	// This list is surely very long and useless when we are using opportunities, so we hide it for this use case, but we allow to show it if
+	// we really want it and to allow interface backward compatibility.
 	print '<br>';
 
 	print_projecttasks_array($db, $form, $socid, $projectsListId, 0, 1, $listofoppstatus, array());