Fix modifying url when it's not set

Signed-off-by: Diego Andrés <diegoandres_cortes@outlook.com>

Author: DiegoAndresCortes

CHANGELOG.md

@@ -1,5 +1,8 @@
 # Changelog
 
+### 4.3.2 - 05 July 2023
+- ![Bug Fix](https://smftricks.com/assets/changelog/bug--minus.png) Fixed modifying 'New Topic' url when it's not set.
+
 ### 4.3.1 - 02 June 2023
 - ![Translation](https://smftricks.com/assets/changelog/language.png) Italian translation provided by [Darknico](https://www.simplemachines.org/community/index.php?action=profile;u=29200)
 - ![Translation](https://smftricks.com/assets/changelog/language.png) Updated translations.

Sources/PostPrefix/Integration/MessageIndex.php

@@ -233,7 +233,7 @@ public function topics_prefixes() : void
 			return;
 
 		// If there's a prefix filtered, pre-select it for a new topic.
-		if (isset($_REQUEST['prefix']) && !empty($_REQUEST['prefix']))
+		if (isset($_REQUEST['prefix']) && !empty($_REQUEST['prefix']) && $context['can_post_new'])
 			$context['normal_buttons']['new_topic']['url'] .= ';prefix=' . $_REQUEST['prefix'];
 
 		// Okay, search the prefixes

package-info.xml

@@ -3,7 +3,7 @@
 <package-info xmlns="http://www.simplemachines.org/xml/package-info" xmlns:smf="http://www.simplemachines.org/">
 	<id>smftricks:postprefix</id>
 	<name>SMF Post Prefix</name>
-	<version>4.3.1</version>
+	<version>4.3.2</version>
 	<type>modification</type>
 	<install for="2.1 - 2.1.99">
 		<!-- Throw error if PHP version too old -->