When this happens, the thread dump is :

Full thread dump Java HotSpot(TM) 64-Bit Server VM (20.10-b01 mixed mode):

"refresh" daemon prio=10 tid=0x00007f0014602800 nid=0xd505 in Object.wait() [0x00007effe7efd000]
   java.lang.Thread.State: WAITING (on object monitor)
    at java.lang.Object.wait(Native Method)
    - waiting on <0x00000000ea536b38> (a java.util.ArrayList)
    at java.lang.Object.wait(Object.java:485)
    at com.common.vcontrol.RefreshManager.checkRequest(RefreshManager.java:115)
    - locked <0x00000000ea536b38> (a java.util.ArrayList)
    at com.common.vcontrol.RefreshManager$2.run(RefreshManager.java:139)

"DestroyJavaVM" prio=10 tid=0x00007f0064010000 nid=0xd4db waiting on condition [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

"Thread-14" daemon prio=10 tid=0x00007f00144e0000 nid=0xd503 in Object.wait() [0x00007f002965c000]
   java.lang.Thread.State: WAITING (on object monitor)
    at java.lang.Object.wait(Native Method)
    - waiting on <0x00000000e9da0648> (a java.util.LinkedList)
    at java.lang.Object.wait(Object.java:485)
    at java.util.prefs.AbstractPreferences$EventDispatchThread.run(AbstractPreferences.java:1461)
    - locked <0x00000000e9da0648> (a java.util.LinkedList)

"fluid terminal" prio=10 tid=0x00007f0014695000 nid=0xd500 in Object.wait() [0x00007effe7cfb000]
   java.lang.Thread.State: TIMED_WAITING (on object monitor)
    at java.lang.Object.wait(Native Method)
    - waiting on <0x00000000ea817bc0> (a java.io.PipedInputStream)
    at java.io.PipedInputStream.read(PipedInputStream.java:310)
    - locked <0x00000000ea817bc0> (a java.io.PipedInputStream)
    at java.io.PipedInputStream.read(PipedInputStream.java:361)
    - locked <0x00000000ea817bc0> (a java.io.PipedInputStream)
    at sun.nio.cs.StreamDecoder.readBytes(StreamDecoder.java:264)
    at sun.nio.cs.StreamDecoder.implRead(StreamDecoder.java:306)
    at sun.nio.cs.StreamDecoder.read(StreamDecoder.java:158)
    - locked <0x00000000ea817ba8> (a java.io.InputStreamReader)
    at java.io.InputStreamReader.read(InputStreamReader.java:167)
    at java.io.Reader.read(Reader.java:123)
    at com.common.terminal.api.AbstractTerminalWrapper._scanServerResponseInLoop(AbstractTerminalWrapper.java:279)
    at com.aquafold.datastudio.tools.shell.FluidTerminalWrapper.loop(FluidTerminalWrapper.java:90)
    at com.aquafold.datastudio.tools.shell.FluidTerminalWrapper$1.run(FluidTerminalWrapper.java:57)

"shell" prio=10 tid=0x00007f00141e0800 nid=0xd4ff waiting on condition [0x00007effe7dfc000]
   java.lang.Thread.State: WAITING (parking)
    at sun.misc.Unsafe.park(Native Method)
    - parking to wait for  <0x00000000ea8177c0> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
    at java.util.concurrent.locks.LockSupport.park(LockSupport.java:156)
    at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:1987)
    at java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:399)
    at com.aquafold.datastudio.tools.shell.CommandLineInterpreter.loop(CommandLineInterpreter.java:1527)
    at com.aquafold.datastudio.tools.shell.CLILoopThread.run(CLILoopThread.java:21)

"XYL" prio=10 tid=0x00007f0014100800 nid=0xd4fc waiting on condition [0x00007f00281d3000]
   java.lang.Thread.State: TIMED_WAITING (sleeping)
    at java.lang.Thread.sleep(Native Method)
    at com.aquafold.datastudio.core.license.LicenseServer.run(LicenseServer.java:272)

"Thread-8" daemon prio=10 tid=0x00007f001488c800 nid=0xd4fa waiting on condition [0x00007f002975d000]
   java.lang.Thread.State: TIMED_WAITING (parking)
    at sun.misc.Unsafe.park(Native Method)
    - parking to wait for  <0x00000000ea891240> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
    at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:196)
    at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2025)
    at java.util.concurrent.DelayQueue.take(DelayQueue.java:164)
    at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:609)
    at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:602)
    at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:947)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:907)
    at java.lang.Thread.run(Thread.java:662)

"TimerQueue" daemon prio=10 tid=0x00007efff8001800 nid=0xd4f5 in Object.wait() [0x00007f002995f000]
   java.lang.Thread.State: TIMED_WAITING (on object monitor)
    at java.lang.Object.wait(Native Method)
    - waiting on <0x00000000ea6d9a60> (a javax.swing.TimerQueue)
    at javax.swing.TimerQueue.run(TimerQueue.java:232)
    - locked <0x00000000ea6d9a60> (a javax.swing.TimerQueue)
    at java.lang.Thread.run(Thread.java:662)

"Parsing & Indexing Loop (null)" daemon prio=10 tid=0x00007f0004004800 nid=0xd4f4 waiting on condition [0x00007f0029f3d000]
   java.lang.Thread.State: WAITING (parking)
    at sun.misc.Unsafe.park(Native Method)
    - parking to wait for  <0x00000000e9db9db0> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
    at java.util.concurrent.locks.LockSupport.park(LockSupport.java:156)
    at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:1987)
    at java.util.concurrent.PriorityBlockingQueue.take(PriorityBlockingQueue.java:220)
    at org.netbeans.modules.parsing.impl.TaskProcessor$CompilationJob.run(TaskProcessor.java:715)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:441)
    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
    at java.util.concurrent.FutureTask.run(FutureTask.java:138)
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
    at java.lang.Thread.run(Thread.java:662)

"Active Reference Queue Daemon" daemon prio=10 tid=0x00007f00145eb800 nid=0xd4f2 in Object.wait() [0x00007f0029a60000]
   java.lang.Thread.State: WAITING (on object monitor)
    at java.lang.Object.wait(Native Method)
    - waiting on <0x00000000ea188350> (a java.lang.ref.ReferenceQueue$Lock)
    at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:118)
    - locked <0x00000000ea188350> (a java.lang.ref.ReferenceQueue$Lock)
    at org.openide.util.lookup.implspi.ActiveQueue$Impl.run(ActiveQueue.java:101)
    at java.lang.Thread.run(Thread.java:662)

"RequestProcessor queue manager" daemon prio=10 tid=0x00007f001404e800 nid=0xd4f1 in Object.wait() [0x00007f0029b61000]
   java.lang.Thread.State: WAITING (on object monitor)
    at java.lang.Object.wait(Native Method)
    - waiting on <0x00000000ea3e4958> (a org.openide.util.RequestProcessor$TickTac)
    at java.lang.Object.wait(Object.java:485)
    at org.openide.util.RequestProcessor$TickTac.obtainFirst(RequestProcessor.java:2213)
    - locked <0x00000000ea3e4958> (a org.openide.util.RequestProcessor$TickTac)
    at org.openide.util.RequestProcessor$TickTac.run(RequestProcessor.java:2200)

"Timer-0" daemon prio=10 tid=0x00007f0064976800 nid=0xd4f0 in Object.wait() [0x00007f0029c62000]
   java.lang.Thread.State: WAITING (on object monitor)
    at java.lang.Object.wait(Native Method)
    - waiting on <0x00000000ea3e4e18> (a java.util.TaskQueue)
    at java.lang.Object.wait(Object.java:485)
    at java.util.TimerThread.mainLoop(Timer.java:483)
    - locked <0x00000000ea3e4e18> (a java.util.TaskQueue)
    at java.util.TimerThread.run(Timer.java:462)

"AWT-EventQueue-0" prio=10 tid=0x00007f00648a8000 nid=0xd4ef runnable [0x00007f002a245000]
   java.lang.Thread.State: RUNNABLE
    at org.netbeans.modules.editor.lib2.highlighting.DirectMergeContainer$HlSequence.updateMergeVars(DirectMergeContainer.java:279)
    at org.netbeans.modules.editor.lib2.highlighting.DirectMergeContainer$HlSequence.nextMerge(DirectMergeContainer.java:255)
    at org.netbeans.modules.editor.lib2.highlighting.DirectMergeContainer$HlSequence.moveNext(DirectMergeContainer.java:202)
    at org.netbeans.modules.editor.lib2.highlighting.HighlightsReader.readUntil(HighlightsReader.java:77)
    at org.netbeans.modules.editor.lib2.view.HighlightsViewFactory.restart(HighlightsViewFactory.java:186)
    at org.netbeans.modules.editor.lib2.view.ViewBuilder$FactoryState.init(ViewBuilder.java:1324)
    at org.netbeans.modules.editor.lib2.view.ViewBuilder.createViews(ViewBuilder.java:721)
    at org.netbeans.modules.editor.lib2.view.ViewBuilder.createReplaceRepaintViews(ViewBuilder.java:684)
    at org.netbeans.modules.editor.lib2.view.ViewUpdates.initParagraphs(ViewUpdates.java:218)
    at org.netbeans.modules.editor.lib2.view.DocumentViewOp.initParagraphs(DocumentViewOp.java:562)
    at org.netbeans.modules.editor.lib2.view.DocumentViewChildren.ensureParagraphsChildrenAndLayoutValid(DocumentViewChildren.java:523)
    at org.netbeans.modules.editor.lib2.view.DocumentViewChildren.ensureParagraphViewChildrenValid(DocumentViewChildren.java:282)
    at org.netbeans.modules.editor.lib2.view.DocumentViewChildren.viewToModelChecked(DocumentViewChildren.java:326)
    at org.netbeans.modules.editor.lib2.view.DocumentView.viewToModelNeedsLock(DocumentView.java:832)
    at org.netbeans.modules.editor.lib2.view.DocumentView.viewToModelChecked(DocumentView.java:819)
    at org.netbeans.modules.editor.lib2.view.EditorView.viewToModel(EditorView.java:343)
    at javax.swing.plaf.basic.BasicTextUI$RootView.viewToModel(BasicTextUI.java:1540)
    at javax.swing.plaf.basic.BasicTextUI.viewToModel(BasicTextUI.java:1089)
    at javax.swing.plaf.basic.BasicTextUI.viewToModel(BasicTextUI.java:1062)
    at javax.swing.text.JTextComponent.viewToModel(JTextComponent.java:1418)
    at org.netbeans.modules.editor.errorstripe.AnnotationView.viewToModel(AnnotationView.java:612)
    at org.netbeans.modules.editor.errorstripe.AnnotationView.getMarkForPointImpl(AnnotationView.java:644)
    at org.netbeans.modules.editor.errorstripe.AnnotationView.getMarkForPoint(AnnotationView.java:674)
    at org.netbeans.modules.editor.errorstripe.AnnotationView.checkCursor(AnnotationView.java:746)
    at org.netbeans.modules.editor.errorstripe.AnnotationView.mouseEntered(AnnotationView.java:725)
    at java.awt.AWTEventMulticaster.mouseEntered(AWTEventMulticaster.java:282)
    at java.awt.Component.processMouseEvent(Component.java:6306)
    at javax.swing.JComponent.processMouseEvent(JComponent.java:3275)
    at java.awt.Component.processEvent(Component.java:6062)
    at java.awt.Container.processEvent(Container.java:2039)
    at java.awt.Component.dispatchEventImpl(Component.java:4660)
    at java.awt.Container.dispatchEventImpl(Container.java:2097)
    at java.awt.Component.dispatchEvent(Component.java:4488)
    at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4575)
    at java.awt.LightweightDispatcher.trackMouseEnterExit(Container.java:4364)
    at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4218)
    at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4166)
    at java.awt.Container.dispatchEventImpl(Container.java:2083)
    at java.awt.Window.dispatchEventImpl(Window.java:2489)
    at java.awt.Component.dispatchEvent(Component.java:4488)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:668)
    at java.awt.EventQueue.access$400(EventQueue.java:81)
    at java.awt.EventQueue$2.run(EventQueue.java:627)
    at java.awt.EventQueue$2.run(EventQueue.java:625)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87)
    at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:98)
    at java.awt.EventQueue$3.run(EventQueue.java:641)
    at java.awt.EventQueue$3.run(EventQueue.java:639)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:638)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)

"AWT-Shutdown" prio=10 tid=0x00007f00648a5000 nid=0xd4ee in Object.wait() [0x00007f002a348000]
   java.lang.Thread.State: WAITING (on object monitor)
    at java.lang.Object.wait(Native Method)
    - waiting on <0x00000000e9f3dd10> (a java.lang.Object)
    at java.lang.Object.wait(Object.java:485)
    at sun.awt.AWTAutoShutdown.run(AWTAutoShutdown.java:265)
    - locked <0x00000000e9f3dd10> (a java.lang.Object)
    at java.lang.Thread.run(Thread.java:662)

"AWT-XAWT" daemon prio=10 tid=0x00007f0064894800 nid=0xd4ec runnable [0x00007f002a660000]
   java.lang.Thread.State: RUNNABLE
    at sun.awt.X11.XToolkit.waitForEvents(Native Method)
    at sun.awt.X11.XToolkit.run(XToolkit.java:579)
    at sun.awt.X11.XToolkit.run(XToolkit.java:543)
    at java.lang.Thread.run(Thread.java:662)

"Java2D Disposer" daemon prio=10 tid=0x00007f0064832800 nid=0xd4eb in Object.wait() [0x00007f002ad90000]
   java.lang.Thread.State: WAITING (on object monitor)
    at java.lang.Object.wait(Native Method)
    - waiting on <0x00000000ea161558> (a java.lang.ref.ReferenceQueue$Lock)
    at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:118)
    - locked <0x00000000ea161558> (a java.lang.ref.ReferenceQueue$Lock)
    at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:134)
    at sun.java2d.Disposer.run(Disposer.java:127)
    at java.lang.Thread.run(Thread.java:662)

"garbage master" prio=10 tid=0x00007f00647f1800 nid=0xd4ea in Object.wait() [0x00007f00602f2000]
   java.lang.Thread.State: WAITING (on object monitor)
    at java.lang.Object.wait(Native Method)
    - waiting on <0x00000000e9f4a878> (a java.util.TaskQueue)
    at java.lang.Object.wait(Object.java:485)
    at java.util.TimerThread.mainLoop(Timer.java:483)
    - locked <0x00000000e9f4a878> (a java.util.TaskQueue)
    at java.util.TimerThread.run(Timer.java:462)

"Monitor Ctrl-Break" daemon prio=10 tid=0x00007f0064735800 nid=0xd4e8 runnable [0x00007f00609d0000]
   java.lang.Thread.State: RUNNABLE
    at java.net.SocketInputStream.socketRead0(Native Method)
    at java.net.SocketInputStream.read(SocketInputStream.java:129)
    at sun.nio.cs.StreamDecoder.readBytes(StreamDecoder.java:264)
    at sun.nio.cs.StreamDecoder.implRead(StreamDecoder.java:306)
    at sun.nio.cs.StreamDecoder.read(StreamDecoder.java:158)
    - locked <0x00000000f9f63d90> (a java.io.InputStreamReader)
    at java.io.InputStreamReader.read(InputStreamReader.java:167)
    at java.io.BufferedReader.fill(BufferedReader.java:136)
    at java.io.BufferedReader.readLine(BufferedReader.java:299)
    - locked <0x00000000f9f63d90> (a java.io.InputStreamReader)
    at java.io.BufferedReader.readLine(BufferedReader.java:362)
    at com.intellij.rt.execution.application.AppMain$1.run(AppMain.java:85)
    at java.lang.Thread.run(Thread.java:662)

"Low Memory Detector" daemon prio=10 tid=0x00007f006409a000 nid=0xd4e6 runnable [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

"C2 CompilerThread1" daemon prio=10 tid=0x00007f0064098000 nid=0xd4e5 waiting on condition [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

"C2 CompilerThread0" daemon prio=10 tid=0x00007f0064095000 nid=0xd4e4 waiting on condition [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

"Signal Dispatcher" daemon prio=10 tid=0x00007f0064093000 nid=0xd4e3 waiting on condition [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

"Finalizer" daemon prio=10 tid=0x00007f0064076800 nid=0xd4e2 in Object.wait() [0x00007f0068b7f000]
   java.lang.Thread.State: WAITING (on object monitor)
    at java.lang.Object.wait(Native Method)
    - waiting on <0x00000000ea48c4a0> (a java.lang.ref.ReferenceQueue$Lock)
    at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:118)
    - locked <0x00000000ea48c4a0> (a java.lang.ref.ReferenceQueue$Lock)
    at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:134)
    at java.lang.ref.Finalizer$FinalizerThread.run(Finalizer.java:159)

"Reference Handler" daemon prio=10 tid=0x00007f0064074800 nid=0xd4e1 in Object.wait() [0x00007f0068c80000]
   java.lang.Thread.State: WAITING (on object monitor)
    at java.lang.Object.wait(Native Method)
    - waiting on <0x00000000ea48c460> (a java.lang.ref.Reference$Lock)
    at java.lang.Object.wait(Object.java:485)
    at java.lang.ref.Reference$ReferenceHandler.run(Reference.java:116)
    - locked <0x00000000ea48c460> (a java.lang.ref.Reference$Lock)

"VM Thread" prio=10 tid=0x00007f006406e000 nid=0xd4e0 runnable

"GC task thread#0 (ParallelGC)" prio=10 tid=0x00007f0064023000 nid=0xd4dc runnable

"GC task thread#1 (ParallelGC)" prio=10 tid=0x00007f0064025000 nid=0xd4dd runnable

"GC task thread#2 (ParallelGC)" prio=10 tid=0x00007f0064027000 nid=0xd4de runnable

"GC task thread#3 (ParallelGC)" prio=10 tid=0x00007f0064028800 nid=0xd4df runnable

"VM Periodic Task Thread" prio=10 tid=0x00007f00640a5000 nid=0xd4e7 waiting on condition

JNI global references: 3042

Heap
 PSYoungGen      total 78464K, used 30193K [0x00000000f8960000, 0x00000000fe710000, 0x0000000100000000)
  eden space 71488K, 32% used [0x00000000f8960000,0x00000000fa01a210,0x00000000fcf30000)
  from space 6976K, 99% used [0x00000000fd150000,0x00000000fd812280,0x00000000fd820000)
  to   space 12224K, 0% used [0x00000000fdb20000,0x00000000fdb20000,0x00000000fe710000)
 PSOldGen        total 128128K, used 63767K [0x00000000e9c00000, 0x00000000f1920000, 0x00000000f8960000)
  object space 128128K, 49% used [0x00000000e9c00000,0x00000000eda45d70,0x00000000f1920000)
 PSPermGen       total 114432K, used 96236K [0x00000000ddc00000, 0x00000000e4bc0000, 0x00000000e9c00000)
  object space 114432K, 84% used [0x00000000ddc00000,0x00000000e39fb208,0x00000000e4bc0000)

The java editor locks ADS because it enters an infinite loop while rendering the highlight views. Fixed this issue on Vincaed 3.0.5.1.

In order to reproduce this issue, there is a simpler scenario:

1. open file attached to this issue;
2. scroll down to bottom;
3. perform some scroll-up actions.

Verified in 12.0.0-rc-23-16