! Fixed theme selector to work with more variants - Thanks Akyhne for both the report and the fix

Sources/Themes.php

@@ -1046,6 +1046,10 @@ function PickTheme()
 		// Change a specific member's theme.
 		else
 		{
+			// The forum's default theme is always 0 and we 
+			if (isset($_GET['th']) && $_GET['th'] == 0)
+					$_GET['th'] = $modSettings['theme_guests'];
+
 			updateMemberData((int) $_REQUEST['u'], array('id_theme' => (int) $_GET['th']));
 
 			if (!empty($_GET['vrt']))

Themes/default/Themes.template.php

@@ -651,7 +651,7 @@ function template_pick()
 		echo '
 			<div class="cat_bar">
 				<h3 class="catbg">
-					<a href="', $scripturl, '?action=theme;sa=pick;u=', $context['current_member'], ';th=', $theme['id'], ';', $context['session_var'], '=', $context['session_id'], '">', $theme['name'], '</a>
+					<a href="', $scripturl, '?action=theme;sa=pick;u=', $context['current_member'], ';th=', $theme['id'], ';', $context['session_var'], '=', $context['session_id'], !empty($theme['variants']) ? ';vrt=' . $theme['selected_variant'] : '', '">', $theme['name'], '</a>
 				</h3>
 			</div>
 			<div class="', $theme['selected'] ? 'windowbg' : 'windowbg2', '">
@@ -686,7 +686,7 @@ function template_pick()
 					<br />
 					<ul class="reset">
 						<li>
-							<a href="', $scripturl, '?action=theme;sa=pick;u=', $context['current_member'], ';th=', $theme['id'], ';', $context['session_var'], '=', $context['session_id'], '" id="theme_use_', $theme['id'], '">[', $txt['theme_set'], ']</a>
+							<a href="', $scripturl, '?action=theme;sa=pick;u=', $context['current_member'], ';th=', $theme['id'], ';', $context['session_var'], '=', $context['session_id'], !empty($theme['variants']) ? ';vrt=' . $theme['selected_variant'] : '', '" id="theme_use_', $theme['id'], '">[', $txt['theme_set'], ']</a>
 						</li>
 						<li>
 							<a href="', $scripturl, '?action=theme;sa=pick;u=', $context['current_member'], ';theme=', $theme['id'], ';', $context['session_var'], '=', $context['session_id'], '" id="theme_preview_', $theme['id'], '">[', $txt['theme_preview'], ']</a>
@@ -700,8 +700,8 @@ function template_pick()
 		{
 			echo '
 			<script type="text/javascript"><!-- // --><![CDATA[
-			var sBaseUseUrl = smf_prepareScriptUrl(smf_scripturl) + \'action=theme;sa=pick;u=', $context['current_member'], ';th=', $theme['id'], ';', $context['session_var'], '=', $context['session_id'], '\';
-			var sBasePreviewUrl = smf_prepareScriptUrl(smf_scripturl) + \'action=theme;sa=pick;u=', $context['current_member'], ';theme=', $theme['id'], ';', $context['session_var'], '=', $context['session_id'], '\';
+			var sBaseUseUrl', $theme['id'], ' = smf_prepareScriptUrl(smf_scripturl) + \'action=theme;sa=pick;u=', $context['current_member'], ';th=', $theme['id'], ';', $context['session_var'], '=', $context['session_id'], '\';
+			var sBasePreviewUrl', $theme['id'], ' = smf_prepareScriptUrl(smf_scripturl) + \'action=theme;sa=pick;u=', $context['current_member'], ';theme=', $theme['id'], ';', $context['session_var'], '=', $context['session_id'], '\';
 			var oThumbnails', $theme['id'], ' = {';
 
 			// All the variant thumbnails.
@@ -719,9 +719,9 @@ function template_pick()
 			function changeVariant', $theme['id'], '(sVariant)
 			{
 				document.getElementById(\'theme_thumb_', $theme['id'], '\').src = oThumbnails', $theme['id'], '[sVariant];
-				document.getElementById(\'theme_use_', $theme['id'], '\').href = sBaseUseUrl + \';vrt=\' + sVariant;
-				document.getElementById(\'theme_thumb_preview_', $theme['id'], '\').href = sBasePreviewUrl + \';vrt=\' + sVariant + \';variant=\' + sVariant;
-				document.getElementById(\'theme_preview_', $theme['id'], '\').href = sBasePreviewUrl + \';vrt=\' + sVariant + \';variant=\' + sVariant;
+				document.getElementById(\'theme_use_', $theme['id'], '\').href = sBaseUseUrl', $theme['id'], ' + \';vrt=\' + sVariant;
+				document.getElementById(\'theme_thumb_preview_', $theme['id'], '\').href = sBasePreviewUrl', $theme['id'], ' + \';vrt=\' + sVariant + \';variant=\' + sVariant;
+				document.getElementById(\'theme_preview_', $theme['id'], '\').href = sBasePreviewUrl', $theme['id'], ' + \';vrt=\' + sVariant + \';variant=\' + sVariant;
 			}
 			// ]]></script>';
 		}