Hi, I wonder if either there is something wrong in my code below, or if I found a bug in morphic or spec. I expect to get a halt when drag&dropping an item from the tree into the button but nothing happens: | buttonModel treeModel ui uiLayout | ui := DynamicComposableModel new. treeModel := ui newTree roots: (1 to: 15); dragEnabled: true; yourself. buttonModel := ui newButton label: 'Drop here'; dropEnabled: true; icon: Smalltalk ui icons smallAddIcon; action: [ self halt ]; acceptDropBlock: [ self halt ]; wantDropBlock: [ self halt ]; dragTransformationBlock: [ self halt ]; yourself. ui assign: treeModel to: #treeModel. ui assign: buttonModel to: #buttonModel. uiLayout := SpecLayout composed newColumn: [ :column | column newRow: #treeModel; newRow: #buttonModel height: ui class buttonHeight ]; yourself. ui openWithSpecLayout: uiLayout. Thanks, MartÃn