25 Oct 2000,   xxxxx@xxxxx   -- still present in the 1.3.1 sources (see Comments section)

java version "1.3.0"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.3.0-C)
Java HotSpot(TM) Client VM (build 1.3.0-C, mixed mode)

There is a bug in DefaultPopupFactory.java, method PanelPopup.hide(), line 956.
If parent is null, it throws a NullPointerException.

After this happens once, mouse motion over JTables and JTrees generates
numerous exceptions, and all JTables and Trees become unusable after that (at
least in my application).

DefaultPopupFactory.java:

line#
----
951        public void hide() {
952            Container parent = getParent();
953            Rectangle r = this.getBounds();
954            if(parent != null)
955                parent.remove(this);
956 bug ==>    parent.repaint(r.x,r.y,r.width,r.height);
957        }
(Review ID: 111382) 
======================================================================

N/A

This was fixed with the restructuring of the code as part of 4303635. Refer to it for more details on how the code has changed.
  xxxxx@xxxxx   2000-11-27

It would be a whole lot easier to work around this type of bugs
if properties like popupFactory of ToolTipManager could be set.
After all, there is an interface PopupFactory but the reference
to it is private in ToolTipManger and set to a DefaultPopupFactory
during construction. If the "default" is going to be that final, it had better 
not contain any bugs ;-) And by the way, shouldn't hide() be replaced by
setVisible(false)?

I cannot understand how this bug can be claimed to be fixed 
when the source for DefaultPopupFactory in JDK 1.3.1_03 is 
as follows:
         
        public void hide() {
            Container parent = getParent();
            Rectangle r = this.getBounds();
            if(parent != null)
                parent.remove(this);
            parent.repaint(r.x,r.y,r.width,r.height);
        }