The TManagedFormImageListEditor class descends from TManagedForm and is only used for the Image List Editor in Delphi 6. It has one protected method MakeComponentsResizable which overrides the empty method of its parent class. To make the form sizeable it must change the Anchors property of the components to make them move in a meaningful way. Unfortunately this is very limited because the ImageView’s height cannot be changed without messing up the sort order of the icons (I tried to fix that but failed). So the form enhancement only allows changing the width and not the height of the form.