after clicking on a file in the explorer, a tooltip came up
and the ide froze

Full thread dump Java HotSpot(TM) Client VM (1.4.1-rc-b19 mixed mode):

"Inactive RequestProcessor thread" daemon prio=1 tid=0x0x563e7f78 nid=0x4139 in Object.wait() [5533f000..5533f840]
        at java.lang.Object.wait(Native Method)
        - waiting on <0x4451f038> (a java.lang.Object)
        at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:574)
        - locked <0x4451f038> (a java.lang.Object)

"Inactive RequestProcessor thread" daemon prio=1 tid=0x0x563a4390 nid=0x4135 in Object.wait() [55190000..55190840]
        at java.lang.Object.wait(Native Method)
        - waiting on <0x444eb1d8> (a java.lang.Object)
        at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:574)
        - locked <0x444eb1d8> (a java.lang.Object)

"Debugger Request Processor" daemon prio=1 tid=0x0x8885458 nid=0x3b74 in Object.wait() [55211000..55211840]
        at java.lang.Object.wait(Native Method)
        - waiting on <0x487c2550> (a java.util.TreeSet)
        at org.netbeans.modules.debugger.support.util.RequestProcessor$ProcessorThread.run(RequestProcessor.java:526)
        - locked <0x487c2550> (a java.util.TreeSet)

"AntProjectSupport.FiringProcessor" daemon prio=1 tid=0x0x8864a78 nid=0x3a0d in Object.wait() [56125000..56125840]
        at java.lang.Object.wait(Native Method)
        - waiting on <0x46602408> (a java.util.HashMap)
        at org.apache.tools.ant.module.xml.AntProjectSupport$FiringProcessor.run(AntProjectSupport.java:618)
        - locked <0x46602408> (a java.util.HashMap)

"Compilation" daemon prio=1 tid=0x0x5635fee0 nid=0x3900 in Object.wait() [553c2000..553c2840]
        at java.lang.Object.wait(Native Method)
        - waiting on <0x49241e60> (a java.util.LinkedList)
        at java.lang.Object.wait(Object.java:426)
        at org.netbeans.core.compiler.CompilationEngineImpl$CompilerThread.nextJobAndTask(CompilationEngineImpl.java:172)
        - locked <0x49241e60> (a java.util.LinkedList)
        at org.netbeans.core.compiler.CompilationEngineImpl$CompilerThread.run(CompilationEngineImpl.java:185)

"VCS Commands Execution Thread-4" daemon prio=1 tid=0x0x83e40a8 nid=0x38f4 in Object.wait() [56603000..56603840]
        at java.lang.Object.wait(Native Method)
        - waiting on <0x45398410> (a org.netbeans.modules.vcscore.commands.CommandsThreadsPool)
        at java.lang.Object.wait(Object.java:426)
        at org.netbeans.modules.vcscore.commands.CommandsThreadsPool.run(CommandsThreadsPool.java:59)
        - locked <0x45398410> (a org.netbeans.modules.vcscore.commands.CommandsThreadsPool)
        at java.lang.Thread.run(Thread.java:536)

"VCS Commands Execution Thread-3" daemon prio=1 tid=0x0x83b0280 nid=0x38f1 in Object.wait() [56501000..56501840]
        at java.lang.Object.wait(Native Method)
        - waiting on <0x45398410> (a org.netbeans.modules.vcscore.commands.CommandsThreadsPool)
        at java.lang.Object.wait(Object.java:426)
        at org.netbeans.modules.vcscore.commands.CommandsThreadsPool.run(CommandsThreadsPool.java:59)
        - locked <0x45398410> (a org.netbeans.modules.vcscore.commands.CommandsThreadsPool)
        at java.lang.Thread.run(Thread.java:536)

"VCS Commands Execution Thread-2" daemon prio=1 tid=0x0x83af3e0 nid=0x38f0 in Object.wait() [56480000..56480840]
        at java.lang.Object.wait(Native Method)
        - waiting on <0x45398410> (a org.netbeans.modules.vcscore.commands.CommandsThreadsPool)
        at java.lang.Object.wait(Object.java:426)
        at org.netbeans.modules.vcscore.commands.CommandsThreadsPool.run(CommandsThreadsPool.java:59)
        - locked <0x45398410> (a org.netbeans.modules.vcscore.commands.CommandsThreadsPool)
        at java.lang.Thread.run(Thread.java:536)

"VCS Commands Execution Thread-1" daemon prio=1 tid=0x0x84096a0 nid=0x38ef in Object.wait() [562a8000..562a8840]
        at java.lang.Object.wait(Native Method)
        - waiting on <0x45398410> (a org.netbeans.modules.vcscore.commands.CommandsThreadsPool)
        at java.lang.Object.wait(Object.java:426)
        at org.netbeans.modules.vcscore.commands.CommandsThreadsPool.run(CommandsThreadsPool.java:59)
        - locked <0x45398410> (a org.netbeans.modules.vcscore.commands.CommandsThreadsPool)
        at java.lang.Thread.run(Thread.java:536)

"External Command Output Grabber Processor" daemon prio=1 tid=0x0x8515350 nid=0x38e7 in Object.wait() [56227000..56227840]
        at java.lang.Object.wait(Native Method)
        - waiting on <0x488ed8d0> (a java.util.ArrayList)
        at java.lang.Object.wait(Object.java:426)
        at org.netbeans.modules.vcscore.cmdline.exec.ExternalCommand$OutputGrabbersProcessor.run(ExternalCommand.java:532)
        - locked <0x488ed8d0> (a java.util.ArrayList)
        at org.openide.util.Task.run(Task.java:136)
        at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:599)

"TimerQueue" daemon prio=1 tid=0x0x82db580 nid=0x38e4 in Object.wait() [5568f000..5568f840]
        at java.lang.Object.wait(Native Method)
        - waiting on <0x45680a88> (a javax.swing.TimerQueue)
        at javax.swing.TimerQueue.run(TimerQueue.java:231)
        - locked <0x45680a88> (a javax.swing.TimerQueue)
        at java.lang.Thread.run(Thread.java:536)

"VCS Commands Execution Thread-0" daemon prio=1 tid=0x0x80dde50 nid=0x38e3 in Object.wait() [5560e000..5560e840]
        at java.lang.Object.wait(Native Method)
        - waiting on <0x45398410> (a org.netbeans.modules.vcscore.commands.CommandsThreadsPool)
        at java.lang.Object.wait(Object.java:426)
        at org.netbeans.modules.vcscore.commands.CommandsThreadsPool.run(CommandsThreadsPool.java:59)
        - locked <0x45398410> (a org.netbeans.modules.vcscore.commands.CommandsThreadsPool)
        at java.lang.Thread.run(Thread.java:536)

"VCS Command Executor Starter Loop" daemon prio=1 tid=0x0x80f4518 nid=0x38e2 in Object.wait() [5558d000..5558d840]
        at java.lang.Object.wait(Native Method)
        - waiting on <0x4531b720> (a org.netbeans.modules.vcscore.commands.CommandsPool)
        at java.lang.Object.wait(Object.java:426)
        at org.netbeans.modules.vcscore.commands.CommandsPool.executorStarterLoop(CommandsPool.java:527)
        - locked <0x4531b720> (a org.netbeans.modules.vcscore.commands.CommandsPool)
        at org.netbeans.modules.vcscore.commands.CommandsPool.access$600(CommandsPool.java:48)
        at org.netbeans.modules.vcscore.commands.CommandsPool$5.run(CommandsPool.java:537)
        at java.lang.Thread.run(Thread.java:536)

"VCS Cache Poll Request Processor" daemon prio=1 tid=0x0x8285b38 nid=0x38db in Object.wait() [528fa000..528fa840]
        at java.lang.Object.wait(Native Method)
        - waiting on <0x453791d8> (a java.lang.ref.ReferenceQueue$Lock)
        at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:111)
        - locked <0x453791d8> (a java.lang.ref.ReferenceQueue$Lock)
        at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:127)
        at org.netbeans.modules.vcscore.cache.CacheHandler.run(CacheHandler.java:136)
        at org.openide.util.Task.run(Task.java:136)
        at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:599)

"Thread-4" daemon prio=1 tid=0x0x8534120 nid=0x38da in Object.wait() [52bf5000..52bf5840]
        at java.lang.Object.wait(Native Method)
        - waiting on <0x44dfe558> (a org.netbeans.core.modules.ChangeFirer)
        at java.lang.Object.wait(Object.java:426)
        at org.netbeans.core.modules.ChangeFirer.run(ChangeFirer.java:94)
        - locked <0x44dfe558> (a org.netbeans.core.modules.ChangeFirer)

"Thread-3" daemon prio=1 tid=0x0x82bacf8 nid=0x38d9 in Object.wait() [52b39000..52b39840]
        at java.lang.Object.wait(Native Method)
        - waiting on <0x44cd4d30> (a java.util.TaskQueue)
        at java.util.TimerThread.mainLoop(Timer.java:429)
        - locked <0x44cd4d30> (a java.util.TaskQueue)
        at java.util.TimerThread.run(Timer.java:382)

"AWT-EventQueue-0" prio=1 tid=0x0x82b7bd0 nid=0x38d8 in Object.wait() [52a7c000..52a7d840]
        at java.lang.Object.wait(Native Method)
        - waiting on <0x48770970> (a org.netbeans.modules.java.parser.ParsingSupport$Processor$T)
        at java.lang.Object.wait(Object.java:426)
        at org.openide.util.Task.waitFinished(Task.java:85)
        - locked <0x48770970> (a org.netbeans.modules.java.parser.ParsingSupport$Processor$T)
        at org.openide.src.nodes.SourceChildren.findChild(SourceChildren.java:208)
        at org.openide.nodes.FilterNode$Children.findChild(FilterNode.java:957)
        at org.openide.nodes.Children.getNodes(Children.java:316)
        at org.openide.explorer.view.VisualizerNode.getChildren(VisualizerNode.java:157)
        at org.openide.explorer.view.VisualizerNode.getChildCount(VisualizerNode.java:202)
        at javax.swing.tree.DefaultTreeModel.getChildCount(DefaultTreeModel.java:168)
        at javax.swing.tree.VariableHeightLayoutCache$TreeStateNode.expand(VariableHeightLayoutCache.java:1461)
        at javax.swing.tree.VariableHeightLayoutCache$TreeStateNode.expand(VariableHeightLayoutCache.java:1270)
        at javax.swing.tree.VariableHeightLayoutCache.rebuild(VariableHeightLayoutCache.java:725)
        at javax.swing.tree.VariableHeightLayoutCache.treeStructureChanged(VariableHeightLayoutCache.java:626)
        at javax.swing.plaf.basic.BasicTreeUI$TreeModelHandler.treeStructureChanged(BasicTreeUI.java:2469)
        at javax.swing.tree.DefaultTreeModel.fireTreeStructureChanged(DefaultTreeModel.java:561)
        at javax.swing.tree.DefaultTreeModel.nodeStructureChanged(DefaultTreeModel.java:345)
        at javax.swing.tree.DefaultTreeModel.setRoot(DefaultTreeModel.java:117)
        at org.openide.explorer.view.NodeTreeModel$1.run(NodeTreeModel.java:77)
        at org.openide.util.Mutex.doEvent(Mutex.java:897)
        at org.openide.util.Mutex.readAccess(Mutex.java:230)
        at org.openide.explorer.view.NodeTreeModel.setNode(NodeTreeModel.java:64)
        at org.openide.explorer.view.TreeView.synchronizeRootContext(TreeView.java:626)
        at org.openide.explorer.view.TreeView$TreePropertyListener.react2VisualPropChange(TreeView.java:731)
        at org.openide.explorer.view.TreeView$TreePropertyListener.propertyChange(TreeView.java:719)
        at org.openide.util.WeakListener$PropertyChange.propertyChange(WeakListener.java:286)
        at java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:252)
        at org.openide.explorer.ExplorerManager.setRootContext(ExplorerManager.java:353)
        at org.netbeans.modules.javaview.JavaView.setNewRoot(JavaView.java:119)
        at org.netbeans.modules.javaview.JavaView.doJob(JavaView.java:173)
        at org.netbeans.modules.javaview.JavaView.access$000(JavaView.java:34)
        at org.netbeans.modules.javaview.JavaView$1.propertyChange(JavaView.java:100)
        at java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:252)
        at org.netbeans.core.windows.RegistryImpl.tryFireChanges(RegistryImpl.java:366)
        at org.netbeans.core.windows.RegistryImpl.selectedNodesChanged(RegistryImpl.java:322)
        at org.netbeans.core.windows.WindowManagerImpl$TopComponentManager.setActivatedNodes(WindowManagerImpl.java:1833)
        at org.openide.windows.TopComponent.setActivatedNodes(TopComponent.java:168)
        at org.openide.explorer.ExplorerPanel$PropL.propertyChange(ExplorerPanel.java:253)
        at java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:252)
        at org.openide.explorer.ExplorerManager.setSelectedNodes(ExplorerManager.java:204)
        at org.openide.explorer.ExplorerManager.setSelectedNodes1(ExplorerManager.java:312)
        at org.openide.explorer.ExplorerManager.setExploredContextAndSelection(ExplorerManager.java:272)
        at org.openide.explorer.view.BeanTreeView.selectionChanged(BeanTreeView.java:92)
        at org.openide.explorer.view.TreeView.callSelectionChanged(TreeView.java:613)
        at org.openide.explorer.view.TreeView$TreePropertyListener.run(TreeView.java:887)
        at org.openide.util.Mutex.postRequest(Mutex.java:860)
        at org.openide.util.Mutex.postReadRequest(Mutex.java:349)
        at org.openide.explorer.view.TreeView$TreePropertyListener.valueChanged(TreeView.java:857)
        at javax.swing.tree.DefaultTreeSelectionModel.fireValueChanged(DefaultTreeSelectionModel.java:629)
        at javax.swing.tree.DefaultTreeSelectionModel.notifyPathChange(DefaultTreeSelectionModel.java:1076)
        at javax.swing.tree.DefaultTreeSelectionModel.setSelectionPaths(DefaultTreeSelectionModel.java:287)
        at javax.swing.tree.DefaultTreeSelectionModel.setSelectionPath(DefaultTreeSelectionModel.java:170)
        at javax.swing.JTree.setSelectionPath(JTree.java:1181)
        at javax.swing.plaf.basic.BasicTreeUI.selectPathForEvent(BasicTreeUI.java:2192)
        at javax.swing.plaf.basic.BasicTreeUI$MouseHandler.handleSelection(BasicTreeUI.java:2840)
        at javax.swing.plaf.basic.BasicTreeUI$MouseHandler.mousePressed(BasicTreeUI.java:2801)
        at java.awt.AWTEventMulticaster.mousePressed(AWTEventMulticaster.java:218)
        at java.awt.AWTEventMulticaster.mousePressed(AWTEventMulticaster.java:217)
        at java.awt.AWTEventMulticaster.mousePressed(AWTEventMulticaster.java:217)
        at java.awt.AWTEventMulticaster.mousePressed(AWTEventMulticaster.java:217)
        at java.awt.AWTEventMulticaster.mousePressed(AWTEventMulticaster.java:217)
        at java.awt.Component.processMouseEvent(Component.java:5090)
        at java.awt.Component.processEvent(Component.java:4890)
        at java.awt.Container.processEvent(Container.java:1566)
        at java.awt.Component.dispatchEventImpl(Component.java:3598)
        at java.awt.Container.dispatchEventImpl(Container.java:1623)
        at java.awt.Component.dispatchEvent(Component.java:3439)
        at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:3450)
        at java.awt.LightweightDispatcher.processMouseEvent(Container.java:3162)
        at java.awt.LightweightDispatcher.dispatchEvent(Container.java:3095)
        at java.awt.Container.dispatchEventImpl(Container.java:1609)
        at java.awt.Window.dispatchEventImpl(Window.java:1585)
        at java.awt.Component.dispatchEvent(Component.java:3439)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:450)
        at java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:197)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:150)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:144)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:136)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:99)

"Thread-1" daemon prio=1 tid=0x0x82aefa0 nid=0x38d7 in Object.wait() [529fc000..529fc840]
        at java.lang.Object.wait(Native Method)
        - waiting on <0x44cd4d10> (a java.util.TaskQueue)
        at java.util.TimerThread.mainLoop(Timer.java:429)
        - locked <0x44cd4d10> (a java.util.TaskQueue)
        at java.util.TimerThread.run(Timer.java:382)

"Java2D Disposer" daemon prio=1 tid=0x0x8289e38 nid=0x38d6 in Object.wait() [5297b000..5297b840]
        at java.lang.Object.wait(Native Method)
        - waiting on <0x44cd4d70> (a java.lang.ref.ReferenceQueue$Lock)
        at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:111)
        - locked <0x44cd4d70> (a java.lang.ref.ReferenceQueue$Lock)
        at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:127)
        at sun.java2d.Disposer.run(Disposer.java:97)
        at java.lang.Thread.run(Thread.java:536)

"AWT-Motif" daemon prio=1 tid=0x0x8284238 nid=0x38d4 runnable [52879000..52879840]
        at sun.awt.motif.MToolkit.run(Native Method)
        at java.lang.Thread.run(Thread.java:536)

"AWT-Shutdown" prio=1 tid=0x0x8258650 nid=0x38d3 in Object.wait() [527db000..527db840]
        at java.lang.Object.wait(Native Method)
        - waiting on <0x44c6a770> (a java.lang.Object)
        at java.lang.Object.wait(Object.java:426)
        at sun.awt.AWTAutoShutdown.run(AWTAutoShutdown.java:259)
        - locked <0x44c6a770> (a java.lang.Object)
        at java.lang.Thread.run(Thread.java:536)

"DestroyJavaVM" prio=1 tid=0x0x8052610 nid=0x38c6 waiting on condition [0..bfffd020]

"Signal Dispatcher" daemon prio=1 tid=0x0x8097ed0 nid=0x38cf waiting on condition [0..0]

"Surrogate Locker Thread (CMS)" daemon prio=1 tid=0x0x8095e80 nid=0x38cc runnable [0..4051231c]

"Finalizer" daemon prio=1 tid=0x0x8090610 nid=0x38cb in Object.wait() [50dc7000..50dc7840]
        at java.lang.Object.wait(Native Method)
        - waiting on <0x44bd8128> (a java.lang.ref.ReferenceQueue$Lock)
        at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:111)
        - locked <0x44bd8128> (a java.lang.ref.ReferenceQueue$Lock)
        at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:127)
        at java.lang.ref.Finalizer$FinalizerThread.run(Finalizer.java:159)

"Reference Handler" daemon prio=1 tid=0x0x808f9c8 nid=0x38ca in Object.wait() [50d46000..50d46840]
        at java.lang.Object.wait(Native Method)
        - waiting on <0x44bd8108> (a java.lang.ref.Reference$Lock)
        at java.lang.Object.wait(Object.java:426)
        at java.lang.ref.Reference$ReferenceHandler.run(Reference.java:113)
        - locked <0x44bd8108> (a java.lang.ref.Reference$Lock)

"VM Thread" prio=1 tid=0x0x808e770 nid=0x38c9 runnable

"VM Periodic Task Thread" prio=1 tid=0x0x8096a00 nid=0x38cd waiting on condition
"Suspend Checker Thread" prio=1 tid=0x0x8097468 nid=0x38ce runnable