Each mdi tab group has a Settings object (or you could set the settings for all groups with UltraTabbedMdiManager.TabGroupSettings) with properties such as CloseButtonAppearance, HotTrackCloseButtonAppearance, and PressedCloseButtonAppearance. You can also set the appearance of these close buttons using AppStylist. By the way, in version 7.3, close button functionality was added so you don't need to use the creation filter in that knowledge base article anymore. Now you can just set the Settings.CloseButtonLocation to Tab.