Description malu 2013-02-13 23:23:33 EST

Created attachment 227054 [details]
Modified org.eclipse.cdt.examples.dsf.filebrowser that can reproduc the reported issue

I have implemented a tree viewer using TreeModelViewer (Virtual type in Lazy mode). I could see a strange behavior while running in Linux OS . If ever I try to expand the tree items using the  API expandAll(), the tree starts blinking/flickering, if it fail to fetch the child nodes. But this behavior was not there in Windows.
 
I tried to debug the code, but it went deep into some infinite loop that always try to update the tree viewer. Please see below the relevant stack trace : 
 
Thread [main] (Suspended)        
OS._gtk_main_do_event(long) line: not available [native method]          
OS.gtk_main_do_event(long) line: 8422               
Display.eventProc(long, long) line: 1245                
OS._gdk_window_process_updates(long, boolean) line: not available [native method] 
OS.gdk_window_process_updates(long, boolean) line: 5511      
Tree(Control).update(boolean, boolean) line: 4975         
Tree(Control).update() line: 4966             
TreeModelViewer(TreeViewer).setExpanded(Item, boolean) line: 335  
TreeModelViewer(AbstractTreeViewer).internalExpandToLevel(Widget, int) line: 1757 
TreeModelViewer(AbstractTreeViewer).expandToLevel(Object, int) line: 1060 
TreeModelViewer(InternalTreeModelViewer).autoExpand(TreePath) line: 2063              
HasChildrenUpdate.performUpdate() line: 53
ViewerUpdateMonitor$1.runInUIThread(IProgressMonitor) line: 99       
UIJob$1.run() line: 95     
 
Steps to reproduce the same in the DSF samples provided (org.eclipse.cdt.examples.dsf.filebrowser). 

1. First I created an empty folder in Linux OS (Fedora 17) say /home/malu/emptyFolder

2. Now in the constructor of file FilesystemRootsVMNode.java, modified the run() method of  update() job so that the root node is 
      File[] files = new File[] {new File("/home/malu/EmptyFolder")};(instead of using API File.listRoots() )

3. Now in FileBrowserDialog.java class I create a sample button too.. along with the search text box. See the snippet below :
     final Button expandAll = new Button(area, SWT.PUSH);
           expandAll.setText("Expand Me");
           expandAll.addSelectionListener(new SelectionAdapter() {
                @Override
                public void widgetSelected(SelectionEvent e) {
                     fViewer.setAutoExpandLevel(ITreeModelViewer.ALL_LEVELS);
                     fViewer.expandAll();
                }
           });

...

Now just run the code, it will show : /home/malu/emptyFolder as root node. Just try to push the "Expand Me" button. We can see the flickering/blinking issue.