nvoked code completion for 'for' and got mangled code, then an exception. After
the exception below the caret was broken again - could type into the document
but the blinking caret did not move and the document never became saveable - may
be a clue about what causes that.

After this, any invocation of actions that would modify the document caused the
exception below. I'm guessing some thread leaves the document permanently locked?

public void addNotify() {
if (fld == null) {
List kids = sfld.getChildren();
Collections.sort (kids, this);
setKeys (kids);
} else {
if (sfld.isEmpty()) {
List keys = new ArrayList (Arrays.asList(fld.getChildren()));
List kids = new ArrayList (keys.size());
for (Iterator it = kids.iterator(); it.hasNext();) {
Object object = it.next();

}for (Iterator it = kids.iterator(); it.hasNext();) {
Object object = it.next();

}for (Iterator it = kids.iterator(); it.hasNext();) {
Object object = it.next();

}for (Iterator it = kids.iterator(); it.hasNext();) {
Object object = it.next();

}
Collections.sort (keys);
setKeys (keys);
} else {
List a = Arrays.asList (fld.getChildren());
List b = sfld.getChildren();
Set combined = new HashSet (a.size() + b.size());
combined.addAll (a);
combined.addAll (b);
List keys = new ArrayList (combined);
Collections.sort (keys, this);
setKeys (keys);
}
}

}

followed by

java.lang.AssertionError: JavaSource.runCompileControlTask called under Document
write lock.
at org.netbeans.api.java.source.JavaSource.runUserActionTask(JavaSource.java:292)
at org.netbeans.api.java.source.JavaSource.getCompilationInfo(JavaSource.java:909)
at org.netbeans.api.java.source.WorkingCopy.(WorkingCopy.java:55)
at org.netbeans.api.java.source.JavaSource.getWorkingCopy(JavaSource.java:431)
at
org.netbeans.modules.editor.java.JavaCodeTemplateProcessor.release(JavaCodeTemplateProcessor.java:111)
at
org.netbeans.lib.editor.codetemplates.CodeTemplateInsertHandler.release(CodeTemplateInsertHandler.java:622)
at
org.netbeans.lib.editor.codetemplates.CodeTemplateInsertHandler.keyPressed(CodeTemplateInsertHandler.java:482)
at java.awt.AWTEventMulticaster.keyPressed(AWTEventMulticaster.java:192)
at java.awt.Component.processKeyEvent(Component.java:5928)
at javax.swing.JComponent.processKeyEvent(JComponent.java:2818)
at java.awt.Component.processEvent(Component.java:5747)
at java.awt.Container.processEvent(Container.java:1984)
at java.awt.Component.dispatchEventImpl(Component.java:4378)
at java.awt.Container.dispatchEventImpl(Container.java:2042)
at java.awt.Component.dispatchEvent(Component.java:4208)
at java.awt.KeyboardFocusManager.redispatchEvent(KeyboardFocusManager.java:1828)
at
java.awt.DefaultKeyboardFocusManager.dispatchKeyEvent(DefaultKeyboardFocusManager.java:693)
at
java.awt.DefaultKeyboardFocusManager.preDispatchKeyEvent(DefaultKeyboardFocusManager.java:952)
at
java.awt.DefaultKeyboardFocusManager.typeAheadAssertions(DefaultKeyboardFocusManager.java:824)
at
java.awt.DefaultKeyboardFocusManager.dispatchEvent(DefaultKeyboardFocusManager.java:657)
at java.awt.Component.dispatchEventImpl(Component.java:4250)
at java.awt.Container.dispatchEventImpl(Container.java:2042)
at java.awt.Window.dispatchEventImpl(Window.java:2299)
at java.awt.Component.dispatchEvent(Component.java:4208)
[catch] at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:273)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:183)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:173)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:168)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:160)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:121)