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我有一个CTabFolder，它包含几个一次性选项卡，每个选项卡都包含一个TreeViewer。我希望每个查看器都有一个DragSupport。所以很自然我用那个方法TreeViewer#addDragSupport。一切都按预期工作，除非我关闭shell并且SWT试图处理所有的小部件。SWT TreeViewer Drag n Drop：处理SWTException小部件
时发生的异常是：
org.eclipse.swt.SWTException: Widget is disposed
at org.eclipse.swt.SWT.error(Unknown Source)
at org.eclipse.swt.SWT.error(Unknown Source)
at org.eclipse.swt.SWT.error(Unknown Source)
at org.eclipse.swt.widgets.Widget.error(Unknown Source)
at org.eclipse.swt.widgets.Widget.checkWidget(Unknown Source)
at org.eclipse.swt.widgets.Widget.removeListener(Unknown Source)
at org.eclipse.swt.dnd.DragSource.onDispose(Unknown Source)
at org.eclipse.swt.dnd.DragSource.access$1(Unknown Source)
at org.eclipse.swt.dnd.DragSource$2.handleEvent(Unknown Source)
at org.eclipse.swt.widgets.EventTable.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.release(Unknown Source)
at org.eclipse.swt.widgets.Widget.dispose(Unknown Source)
at org.eclipse.swt.dnd.DragSource$1.handleEvent(Unknown Source)
at org.eclipse.swt.widgets.EventTable.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.release(Unknown Source)
at org.eclipse.swt.widgets.Composite.releaseChildren(Unknown Source)
at org.eclipse.swt.widgets.Widget.release(Unknown Source)
at org.eclipse.swt.widgets.Composite.releaseChildren(Unknown Source)
at org.eclipse.swt.widgets.Widget.release(Unknown Source)
at org.eclipse.swt.widgets.Widget.dispose(Unknown Source)
at org.eclipse.jface.viewers.ContentViewer.handleDispose(ContentViewer.java:172)
at org.eclipse.jface.viewers.StructuredViewer.handleDispose(StructuredViewer.java:2328)
at org.eclipse.jface.viewers.ContentViewer$2.widgetDisposed(ContentViewer.java:214)
at org.eclipse.swt.widgets.TypedListener.handleEvent(Unknown Source)
at org.eclipse.swt.widgets.EventTable.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.release(Unknown Source)
at org.eclipse.swt.widgets.Composite.releaseChildren(Unknown Source)
at org.eclipse.swt.widgets.Widget.release(Unknown Source)
at org.eclipse.swt.widgets.Composite.releaseChildren(Unknown Source)
at org.eclipse.swt.widgets.Widget.release(Unknown Source)
at org.eclipse.swt.widgets.Widget.dispose(Unknown Source)
at org.eclipse.jface.viewers.ContentViewer.handleDispose(ContentViewer.java:172)
at org.eclipse.jface.viewers.StructuredViewer.handleDispose(StructuredViewer.java:2328)
at org.eclipse.jface.viewers.ContentViewer$2.widgetDisposed(ContentViewer.java:214)
at org.eclipse.swt.widgets.TypedListener.handleEvent(Unknown Source)
at org.eclipse.swt.widgets.EventTable.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.release(Unknown Source)
at org.eclipse.swt.widgets.Composite.releaseChildren(Unknown Source)
at org.eclipse.swt.widgets.Widget.release(Unknown Source)
at org.eclipse.swt.widgets.Composite.releaseChildren(Unknown Source)
at org.eclipse.swt.widgets.Widget.release(Unknown Source)
at org.eclipse.swt.widgets.Widget.dispose(Unknown Source)
at org.eclipse.jface.viewers.ContentViewer.handleDispose(ContentViewer.java:172)
at org.eclipse.jface.viewers.StructuredViewer.handleDispose(StructuredViewer.java:2328)
at org.eclipse.jface.viewers.ContentViewer$2.widgetDisposed(ContentViewer.java:214)
at org.eclipse.swt.widgets.TypedListener.handleEvent(Unknown Source)
at org.eclipse.swt.widgets.EventTable.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.release(Unknown Source)
at org.eclipse.swt.widgets.Composite.releaseChildren(Unknown Source)
at org.eclipse.swt.widgets.Widget.release(Unknown Source)
at org.eclipse.swt.widgets.Composite.releaseChildren(Unknown Source)
at org.eclipse.swt.widgets.Widget.release(Unknown Source)
at org.eclipse.swt.widgets.Widget.dispose(Unknown Source)
at org.eclipse.jface.viewers.ContentViewer.handleDispose(ContentViewer.java:172)
at org.eclipse.jface.viewers.StructuredViewer.handleDispose(StructuredViewer.java:2328)
at org.eclipse.jface.viewers.ContentViewer$2.widgetDisposed(ContentViewer.java:214)
at org.eclipse.swt.widgets.TypedListener.handleEvent(Unknown Source)
at org.eclipse.swt.widgets.EventTable.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.release(Unknown Source)
at org.eclipse.swt.widgets.Composite.releaseChildren(Unknown Source)
at org.eclipse.swt.widgets.Widget.release(Unknown Source)
at org.eclipse.swt.widgets.Composite.releaseChildren(Unknown Source)
at org.eclipse.swt.widgets.Widget.release(Unknown Source)
at org.eclipse.swt.widgets.Composite.releaseChildren(Unknown Source)
at org.eclipse.swt.widgets.Widget.release(Unknown Source)
at org.eclipse.swt.widgets.Composite.releaseChildren(Unknown Source)
at org.eclipse.swt.widgets.Widget.release(Unknown Source)
at org.eclipse.swt.widgets.Composite.releaseChildren(Unknown Source)
at org.eclipse.swt.widgets.Canvas.releaseChildren(Unknown Source)
at org.eclipse.swt.widgets.Decorations.releaseChildren(Unknown Source)
at org.eclipse.swt.widgets.Shell.releaseChildren(Unknown Source)
at org.eclipse.swt.widgets.Widget.release(Unknown Source)
at org.eclipse.swt.widgets.Widget.dispose(Unknown Source)
at org.eclipse.swt.widgets.Decorations.dispose(Unknown Source)
at org.eclipse.swt.widgets.Shell.dispose(Unknown Source)
at org.eclipse.jface.window.Window.close(Window.java:335)
at org.eclipse.jface.window.ApplicationWindow.close(ApplicationWindow.java:307)
at org.eclipse.jface.window.Window.handleShellCloseEvent(Window.java:741)
at org.eclipse.jface.window.Window$3.shellClosed(Window.java:687)
at org.eclipse.swt.widgets.TypedListener.handleEvent(Unknown Source)
at org.eclipse.swt.widgets.EventTable.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Decorations.closeWidget(Unknown Source)
at org.eclipse.swt.widgets.Decorations.WM_CLOSE(Unknown Source)
at org.eclipse.swt.widgets.Control.windowProc(Unknown Source)
at org.eclipse.swt.widgets.Canvas.windowProc(Unknown Source)
at org.eclipse.swt.widgets.Decorations.windowProc(Unknown Source)
at org.eclipse.swt.widgets.Shell.windowProc(Unknown Source)
at org.eclipse.swt.widgets.Display.windowProc(Unknown Source)
at org.eclipse.swt.internal.win32.OS.DefWindowProcW(Native Method)
at org.eclipse.swt.internal.win32.OS.DefWindowProc(Unknown Source)
at org.eclipse.swt.widgets.Shell.callWindowProc(Unknown Source)
at org.eclipse.swt.widgets.Control.windowProc(Unknown Source)
at org.eclipse.swt.widgets.Canvas.windowProc(Unknown Source)
at org.eclipse.swt.widgets.Decorations.windowProc(Unknown Source)
at org.eclipse.swt.widgets.Shell.windowProc(Unknown Source)
at org.eclipse.swt.widgets.Display.windowProc(Unknown Source)
at org.eclipse.swt.internal.win32.OS.DefWindowProcW(Native Method)
at org.eclipse.swt.internal.win32.OS.DefWindowProc(Unknown Source)
at org.eclipse.swt.widgets.Shell.callWindowProc(Unknown Source)
at org.eclipse.swt.widgets.Control.windowProc(Unknown Source)
at org.eclipse.swt.widgets.Canvas.windowProc(Unknown Source)
at org.eclipse.swt.widgets.Decorations.windowProc(Unknown Source)
at org.eclipse.swt.widgets.Shell.windowProc(Unknown Source)
at org.eclipse.swt.widgets.Display.windowProc(Unknown Source)
at org.eclipse.swt.internal.win32.OS.DispatchMessageW(Native Method)
at org.eclipse.swt.internal.win32.OS.DispatchMessage(Unknown Source)
at org.eclipse.swt.widgets.Display.readAndDispatch(Unknown Source)
at org.eclipse.jface.window.Window.runEventLoop(Window.java:825)
at org.eclipse.jface.window.Window.open(Window.java:801)
这似乎有点广泛。看来SWT在处理完毕后会尝试从树中移除DragListener。我真的不明白这怎么可能。
我不认为我犯了一个错误实现源/目标和传输类型，因为拖放和下降的作品就像一个魅力。
将Drag支持添加到包含在一次性Widget中的TreeViewer时，可能需要考虑哪些缺陷？
如果你需要一个代码示例让我知道。