我正在为高级数据网格进行缩进和缩进。我有一组功能，当对基础数据进行操作时可以正常工作，但在对数据网格的选定项目进行操作时会抛出“错误：书签不再有效”。
Error: Bookmark no longer valid.
at ListCollectionViewCursor/seek()[E:\dev\hero_private\frameworks\projects\framework\src\mx\collections\ListCollectionView.as:2429]
at mx.collections::HierarchicalCollectionViewCursor/get current()[E:\dev\hero_private\frameworks\projects\advancedgrids\src\mx\collections\HierarchicalCollectionViewCursor.as:220]
at mx.collections::HierarchicalCollectionViewCursor/collectionChangeHandler()[E:\dev\hero_private\frameworks\projects\advancedgrids\src\mx\collections\HierarchicalCollectionViewCursor.as:1152]
at flash.events::EventDispatcher/dispatchEventFunction()
at flash.events::EventDispatcher/dispatchEvent()
at mx.collections::HierarchicalCollectionView/collectionChangeHandler()[E:\dev\hero_private\frameworks\projects\advancedgrids\src\mx\collections\HierarchicalCollectionView.as:1485]
at flash.events::EventDispatcher/dispatchEventFunction()
at flash.events::EventDispatcher/dispatchEvent()
at mx.collections::ListCollectionView/dispatchEvent()[E:\dev\hero_private\frameworks\projects\framework\src\mx\collections\ListCollectionView.as:1024]
at mx.collections::ListCollectionView/handlePropertyChangeEvents()[E:\dev\hero_private\frameworks\projects\framework\src\mx\collections\ListCollectionView.as:1449]
at mx.collections::ListCollectionView/listChangeHandler()[E:\dev\hero_private\frameworks\projects\framework\src\mx\collections\ListCollectionView.as:1316]
at flash.events::EventDispatcher/dispatchEventFunction()
at flash.events::EventDispatcher/dispatchEvent()
at mx.collections::XMLListAdapter/itemUpdateHandler()[E:\dev\hero_private\frameworks\projects\framework\src\mx\collections\XMLListAdapter.as:623]
at mx.collections::XMLListAdapter/itemUpdated()[E:\dev\hero_private\frameworks\projects\framework\src\mx\collections\XMLListAdapter.as:366]
at mx.collections::XMLListAdapter/xmlNotification()[E:\dev\hero_private\frameworks\projects\framework\src\mx\collections\XMLListAdapter.as:725]
at Function/<anonymous>()[E:\dev\hero_private\frameworks\projects\framework\src\mx\utils\XMLNotifier.as:93]
at com.ibm.ilog.elixir.gantt::GanttChartBase/setItemField()[/data/flex/tools/branches/release-3.5/enterprise/build/product_build/trial_target/installers/enterprise/trial-sources/library/gantt/gantt/src/flex/com/ibm/ilog/elixir/gantt/GanttChartBase.as:1506]
at com.ibm.ilog.elixir.gantt::GanttChartBase/commitTaskItem()[/data/flex/tools/branches/release-3.5/enterprise/build/product_build/trial_target/installers/enterprise/trial-sources/library/gantt/gantt/src/flex/com/ibm/ilog/elixir/gantt/GanttChartBase.as:1458]
at com.ibm.ilog.elixir.gantt::TaskChart/commitTaskItem()[/data/flex/tools/branches/release-3.5/enterprise/build/product_build/trial_target/installers/enterprise/trial-sources/library/gantt/gantt/src/flex/com/ibm/ilog/elixir/gantt/TaskChart.as:1250]
at com.ibm.ilog.elixir.gantt::GanttSheet/commitItem()[/data/flex/tools/branches/release-3.5/enterprise/build/product_build/trial_target/installers/enterprise/trial-sources/library/gantt/gantt/src/flex/com/ibm/ilog/elixir/gantt/GanttSheet.as:10242]
at com.ibm.ilog.elixir.gantt::GanttSheet/resizeSummaryTask()[/data/flex/tools/branches/release-3.5/enterprise/build/product_build/trial_target/installers/enterprise/trial-sources/library/gantt/gantt/src/flex/com/ibm/ilog/elixir/gantt/GanttSheet.as:10399]
at com.ibm.ilog.elixir.gantt::GanttSheet/resizeSummaryTasks()[/data/flex/tools/branches/release-3.5/enterprise/build/product_build/trial_target/installers/enterprise/trial-sources/library/gantt/gantt/src/flex/com/ibm/ilog/elixir/gantt/GanttSheet.as:10302]
at com.ibm.ilog.elixir.gantt::GanttSheet/taskCollection_collectionChangeHandler()[/data/flex/tools/branches/release-3.5/enterprise/build/product_build/trial_target/installers/enterprise/trial-sources/library/gantt/gantt/src/flex/com/ibm/ilog/elixir/gantt/GanttSheet.as:9573]
at flash.events::EventDispatcher/dispatchEventFunction()
at flash.events::EventDispatcher/dispatchEvent()
at mx.collections::HierarchicalCollectionView/nestedCollectionChangeHandler()[E:\dev\hero_private\frameworks\projects\advancedgrids\src\mx\collections\HierarchicalCollectionView.as:1594]
at flash.events::EventDispatcher/dispatchEventFunction()
at flash.events::EventDispatcher/dispatchEvent()
at mx.collections::ListCollectionView/dispatchEvent()[E:\dev\hero_private\frameworks\projects\framework\src\mx\collections\ListCollectionView.as:1024]
at mx.collections::HierarchicalCollectionView/xmlNotification()[E:\dev\hero_private\frameworks\projects\advancedgrids\src\mx\collections\HierarchicalCollectionView.as:1816]
at Function/<anonymous>()[E:\dev\hero_private\frameworks\projects\framework\src\mx\utils\XMLNotifier.as:93]
at com.indven.epm.project.util::CommandsUtil$/movNode()[D:\flash builder workspace\trunk\Sources\FlexSources\src\com\indven\epm\project\util\CommandsUtil.as:346]
at com.indven.epm.project.util::CommandsUtil$/moveUpNode()[D:\flash builder workspace\trunk\Sources\FlexSources\src\com\indven\epm\project\util\CommandsUtil.as:270]
at com.indven.epm.project.util::CommandsUtil$/changeNodeHierarchy()[D:\flash builder workspace\trunk\Sources\FlexSources\src\com\indven\epm\project\util\CommandsUtil.as:109]
at com.indven.epm.project.task.view::TaskDetails/moveUp()[D:\flash builder workspace\trunk\Sources\FlexSources\src\com\indven\epm\project\task\view\TaskDetailsHandler.as:1231]
at com.indven.epm.project.task.view::TaskDetails/___TaskDetails_Button11_click()[D:\flash builder workspace\trunk\Sources\FlexSources\src\com\indven\epm\project\task\view\TaskDetails.mxml:55]`enter code here`