diff --git a/Source/Editor/Windows/Assets/SkeletonMaskWindow.cs b/Source/Editor/Windows/Assets/SkeletonMaskWindow.cs
index a5e3da327..301ccf9b4 100644
--- a/Source/Editor/Windows/Assets/SkeletonMaskWindow.cs
+++ b/Source/Editor/Windows/Assets/SkeletonMaskWindow.cs
@@ -167,23 +167,19 @@ namespace FlaxEditor.Windows.Assets
                     var proxy = (PropertiesProxy)Values[0];
                     int nodeIndex = (int)checkBox.Tag;
                     proxy.NodesMask[nodeIndex] = checkBox.Checked;
-                    if(Input.GetKey(KeyboardKeys.Shift))
+                    if (Input.GetKey(KeyboardKeys.Shift))
                         SetTreeChecked(checkBox.Parent as TreeNode, checkBox.Checked);
                     proxy.Window.MarkAsEdited();
                 }
 
                 private void SetTreeChecked(TreeNode tree, bool state)
                 {
-                    foreach(var node in tree.Children)
+                    foreach (var node in tree.Children)
                     {
-                        if(node is TreeNode)
-                        {
-                            SetTreeChecked(node as TreeNode, state);
-                        }
-                        if(node is CheckBox)
-                        {
-                            (node as CheckBox).Checked = state;
-                        }
+                        if (node is TreeNode treeNode)
+                            SetTreeChecked(treeNode, state);
+                        else if (node is CheckBox checkBox)
+                            checkBox.Checked = state;
                     }
                 }
             }