Index: wp-admin/menu-header.php
===================================================================
--- wp-admin/menu-header.php	(revision 11581)
+++ wp-admin/menu-header.php	(working copy)
@@ -74,7 +74,10 @@
 		} elseif ( $submenu_as_parent && !empty($submenu[$item[2]]) ) {
 			$submenu[$item[2]] = array_values($submenu[$item[2]]);  // Re-index.
 			$menu_hook = get_plugin_page_hook($submenu[$item[2]][0][2], $item[2]);
-			if ( ( ('index.php' != $submenu[$item[2]][0][2]) && file_exists(WP_PLUGIN_DIR . "/{$submenu[$item[2]][0][2]}") ) || !empty($menu_hook)) {
+			$menu_file = $submenu[$item[2]][0][2];
+			if ( false !== $pos = strpos($menu_file, '?') )
+				$menu_file = substr($menu_file, 0, $pos);
+			if ( ( ('index.php' != $submenu[$item[2]][0][2]) && file_exists(WP_PLUGIN_DIR . "/$menu_file") ) || !empty($menu_hook)) {
 				$admin_is_parent = true;
 				echo "<div class='wp-menu-image'><a href='admin.php?page={$submenu[$item[2]][0][2]}'>$img</a></div>$toggle<a href='admin.php?page={$submenu[$item[2]][0][2]}'$class$tabindex>{$item[0]}</a>";
 			} else {
@@ -82,7 +85,10 @@
 			}
 		} else if ( current_user_can($item[1]) ) {
 			$menu_hook = get_plugin_page_hook($item[2], 'admin.php');
-			if ( ('index.php' != $item[2]) && file_exists(WP_PLUGIN_DIR . "/{$item[2]}") || !empty($menu_hook) ) {
+			$menu_file = $item[2];
+			if ( false !== $pos = strpos($menu_file, '?') )
+				$menu_file = substr($menu_file, 0, $pos);
+			if ( ('index.php' != $item[2]) && file_exists(WP_PLUGIN_DIR . "/$menu_file") || !empty($menu_hook) ) {
 				$admin_is_parent = true;
 				echo "\n\t<div class='wp-menu-image'><a href='admin.php?page={$item[2]}'>$img</a></div>$toggle<a href='admin.php?page={$item[2]}'$class$tabindex>{$item[0]}</a>";
 			} else {
@@ -102,22 +108,31 @@
 					$class[] = 'wp-first-item';
 					$first = false;
 				}
+
+				$menu_file = $item[2];
+				if ( false !== $pos = strpos($menu_file, '?') )
+					$menu_file = substr($menu_file, 0, $pos);
+
 				if ( isset($submenu_file) ) {
 					if ( $submenu_file == $sub_item[2] )
 						$class[] = 'current';
 				// If plugin_page is set the parent must either match the current page or not physically exist.
 				// This allows plugin pages with the same hook to exist under different parents.
-				} else if ( (isset($plugin_page) && $plugin_page == $sub_item[2] && (!file_exists($item[2]) || ($item[2] == $self))) || (!isset($plugin_page) && $self == $sub_item[2]) ) {
+				} else if ( (isset($plugin_page) && $plugin_page == $sub_item[2] && (!file_exists($menu_file) || ($item[2] == $self))) || (!isset($plugin_page) && $self == $sub_item[2]) ) {
 					$class[] = 'current';
 				}
 
 				$class = $class ? ' class="' . join( ' ', $class ) . '"' : '';
 
 				$menu_hook = get_plugin_page_hook($sub_item[2], $item[2]);
+				$sub_file = $sub_item[2];
+				if ( false !== $pos = strpos($sub_file, '?') )
+					$sub_file = substr($sub_file, 0, $pos);
 
-				if ( ( ('index.php' != $sub_item[2]) && file_exists(WP_PLUGIN_DIR . "/{$sub_item[2]}") ) || ! empty($menu_hook) ) {
+				if ( ( ('index.php' != $sub_item[2]) && file_exists(WP_PLUGIN_DIR . "/$sub_file") ) || ! empty($menu_hook) ) {
 					// If admin.php is the current page or if the parent exists as a file in the plugins or admin dir
-					$parent_exists = (!$admin_is_parent && file_exists(WP_PLUGIN_DIR . "/{$item[2]}") && !is_dir(WP_PLUGIN_DIR . "/{$item[2]}") ) || file_exists($item[2]);
+					
+					$parent_exists = (!$admin_is_parent && file_exists(WP_PLUGIN_DIR . "/$menu_file") && !is_dir(WP_PLUGIN_DIR . "/{$item[2]}") ) || file_exists($menu_file);
 					if ( $parent_exists )
 						echo "<li$class><a href='{$item[2]}?page={$sub_item[2]}'$class$tabindex>{$sub_item[0]}</a></li>";
 					elseif ( 'admin.php' == $pagenow || !$parent_exists )