[Bug swing/28769] Regression:JTree and JTable mouse-wheel scrolling

[hendrich at informatik dot uni-hamburg dot de]

------- Comment #9 from hendrich at informatik dot uni-hamburg dot de  
2006-10-18 15:15 -------
Hello Roman and Audrius,

first of all, thanks for working on Swing in general, and "my" bugs in
particular. Please don't quarrel about the bugs or the exact state of them.
By now, I am pretty experienced in re-opening bugs when necessary - for
example, right now :-)


> (In reply to comment #8)
> I have just tested the JTree scrolling with fresh CVS check. The scrolling in
> both components with mouse wheel works correctly. Scrolling both up and down 
> is possible, and even the boundary adjustment works as required. 
> The user likely
> tested with the outdated version. I am closing this as no longer
> unreproducible.

Well, I just tested with a fresh cvs checkout again to make sure. This is
on Linux x86 with jamvm and cacao, with my image viewer ("Niffler") as
the text application.

Playing with a large tree with about 4000 nodes (max depth six levels)
shows that expanding and collapsing nodes in the tree works. However,
I also sometimes get NPEs [1] from repaint(), but the tree looks ok.

Basic mouse-wheel scrolling does indeed work now, both up and down,
but scrolling down to the very bottom often "resets" the scrollbar thumb, 
and one can scroll down again... Doesn't happen when scrolling up.
This doesn't happen always. My initial theory is that it happens 
when I use mouse-scrolling after expanding a new subtree, while it
gets fixed when I click or drag the scrollbar.

Is this an effect of the JTree layout cache? If so, please feel free
to close the bug again :-)

(If you bother to test this with my image viewer, please make sure to 
keep the mouse in motion... Otherwise, the HideCursorManager might trigger
and hide the mouse cursor on the image canvas, which wrongly also hides
the cursor in the JTree. I report this as a new bug.)


[1] NPE from repaint:
java.lang.NullPointerException
   at javax.swing.JComponent.repaint(JComponent.java:2889)
   at javax.swing.JTree$TreeSelectionRedirector.valueChanged(JTree.java:1287)
   at
javax.swing.tree.DefaultTreeSelectionModel.fireValueChanged(DefaultTreeSelectionModel.java:769)
   at
javax.swing.tree.DefaultTreeSelectionModel.notifyPathChange(DefaultTreeSelectionModel.java:1163)
   at
javax.swing.tree.DefaultTreeSelectionModel.setSelectionPaths(DefaultTreeSelectionModel.java:461)
   at
javax.swing.tree.DefaultTreeSelectionModel.setSelectionPath(DefaultTreeSelectionModel.java:338)
   at javax.swing.JTree.setSelectionPath(JTree.java:2211)
   at
javax.swing.plaf.basic.BasicTreeUI.selectPathForEvent(BasicTreeUI.java:2095)
   at
javax.swing.plaf.basic.BasicTreeUI$MouseHandler.handleEvent(BasicTreeUI.java:2543)
   at
javax.swing.plaf.basic.BasicTreeUI$MouseHandler.mousePressed(BasicTreeUI.java:2469)
   at java.awt.Component.processMouseEvent(Component.java:3808)
   at java.awt.Component.processEvent(Component.java:3670)
   at java.awt.Container.processEvent(Container.java:1027)
   at java.awt.Component.dispatchEventImpl(Component.java:5737)
   at java.awt.Container.dispatchEventImpl(Container.java:1922)
   at java.awt.Component.dispatchEvent(Component.java:2836)
   at java.awt.LightweightDispatcher.redispatch(LightweightDispatcher.java:325)
   at
java.awt.LightweightDispatcher.handleMouseEvent(LightweightDispatcher.java:151)
   at
java.awt.LightweightDispatcher.dispatchEvent(LightweightDispatcher.java:115)
   at java.awt.Container.dispatchEventImpl(Container.java:1911)
   at java.awt.Window.dispatchEventImpl(Window.java:607)
   at java.awt.Component.dispatchEvent(Component.java:2836)
   at java.awt.EventQueue.dispatchEvent(EventQueue.java:618)
   at java.awt.EventDispatchThread.run(EventDispatchThread.java:85)


-- 

hendrich at informatik dot uni-hamburg dot de changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |UNCONFIRMED
         Resolution|WORKSFORME                  |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28769