diff --git a/core/html_api.php b/core/html_api.php
index 7ece4da..c78c3d3 100644
--- a/core/html_api.php
+++ b/core/html_api.php
@@ -726,7 +726,9 @@ function print_menu() {
 				if( is_array( $t_callback_menu_options ) ) {
 					$t_menu_options = array_merge( $t_menu_options, $t_callback_menu_options );
 				} else {
-					$t_menu_options[] = $t_callback_menu_options;
+					if (!is_null($t_callback_menu_options)) {
+						$t_menu_options[] = $t_callback_menu_options;
+					}
 				}
 			}
 		}
@@ -774,7 +776,9 @@ function print_menu() {
 				if( is_array( $t_callback_menu_options ) ) {
 					$t_menu_options = array_merge( $t_menu_options, $t_callback_menu_options );
 				} else {
-					$t_menu_options[] = $t_callback_menu_options;
+					if (!is_null($t_callback_menu_options)) {
+						$t_menu_options[] = $t_callback_menu_options;
+					}
 				}
 			}
 		}
@@ -899,7 +903,9 @@ function print_summary_submenu() {
 			if( is_array( $t_callback_menu_options ) ) {
 				$t_menu_options = array_merge( $t_menu_options, $t_callback_menu_options );
 			} else {
-				$t_menu_options[] = $t_callback_menu_options;
+				if (!is_null($t_callback_menu_options)) {
+					$t_menu_options[] = $t_callback_menu_options;
+				}				
 			}
 		}
 	}
@@ -984,7 +990,9 @@ function print_manage_menu( $p_page = '' ) {
 			if( is_array( $t_callback_menu_options ) ) {
 				$t_menu_options = array_merge( $t_menu_options, $t_callback_menu_options );
 			} else {
-				$t_menu_options[] = $t_callback_menu_options;
+				if (!is_null($t_callback_menu_options)) {
+					$t_menu_options[] = $t_callback_menu_options;
+				}				
 			}
 		}
 	}
@@ -1096,7 +1104,9 @@ function print_account_menu( $p_page = '' ) {
 			if( is_array( $t_callback_menu_options ) ) {
 				$t_menu_options = array_merge( $t_menu_options, $t_callback_menu_options );
 			} else {
-				$t_menu_options[] = $t_callback_menu_options;
+				if (!is_null($t_callback_menu_options)) {
+					$t_menu_options[] = $t_callback_menu_options;
+				}				
 			}
 		}
 	}
@@ -1157,7 +1167,9 @@ function print_summary_menu( $p_page = '' ) {
 			if( is_array( $t_callback_menu_options ) ) {
 				$t_menu_options = array_merge( $t_menu_options, $t_callback_menu_options );
 			} else {
-				$t_menu_options[] = $t_callback_menu_options;
+				if (!is_null($t_callback_menu_options)) {
+					$t_menu_options[] = $t_callback_menu_options;
+				}				
 			}
 		}
 	}