Index: branches/RC/core/install/step_templates/choose_modules.tpl
===================================================================
diff -u -N -r10924 -r11074
--- branches/RC/core/install/step_templates/choose_modules.tpl	(.../choose_modules.tpl)	(revision 10924)
+++ branches/RC/core/install/step_templates/choose_modules.tpl	(.../choose_modules.tpl)	(revision 11074)
@@ -19,6 +19,7 @@
 <?php
 	$module_tpl = ob_get_clean();
 
+	$first_time = $this->GetVar('step') != $this->currentStep; // data from this step was not submitted yet
 	$selected = $this->GetVar('modules');
 	if (!$selected) {
 		// preselect interface modules
@@ -49,7 +50,7 @@
 		}
 		else {
 			// preserve user selected checked status
-			$checked = in_array($module, $selected) ? 'checked="checked"' : '';
+			$checked = in_array($module, $selected) || $first_time ? 'checked="checked"' : '';
 		}
 
 		$error_msg = $prerequisites_errors ? implode('<br />', $prerequisites_errors) : '';