Description gateway 2004-05-29 18:11:18 EDT

Problem:
--------
DropTarget cleanup (COM-level) does not seem to be complete. Instantiating
another DragDrop instance within the same process
fails after calling CoLockObjectExternal COM API.

org.eclipse.swt.SWTError: Cannot initialize Drop
	at org.eclipse.swt.dnd.DND.error(DND.java:220)
	at org.eclipse.swt.dnd.DND.error(DND.java:181)
	at org.eclipse.swt.dnd.DropTarget.<init>(DropTarget.java:133)
	at
org.eclipse.swt.examples.dnd.DNDExample.createDropTarget(DNDExample.java:640)
	at org.eclipse.swt.examples.dnd.DNDExample.access$2000
(DNDExample.java:21)
	at
org.eclipse.swt.examples.dnd.DNDExample$25.widgetSelected(DNDExample.java:839)
	at
org.eclipse.swt.widgets.TypedListener.handleEvent(TypedListener.java:89)
	at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:82)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:769)
	at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:2578)
	at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:2256)
	at org.eclipse.swt.examples.dnd.DNDExample.open(DNDExample.java:1101)
	at org.eclipse.swt.examples.dnd.DNDExample.access$000
(DNDExample.java:21)
	at org.eclipse.swt.examples.dnd.DNDExample$1.run(DNDExample.java:67)
	at java.lang.Thread.run(Thread.java:534)

Environment:
------------
Windows XP Pro 2002 SP1
SWT M08
j2sdk1.4.2_03

Steps to reproduce:
------------------
1. Modify DNDExample.java (SWT sample), main() method as shown below, so
that 
it displays two Shell instances, one after another:
public static void main(String[] args) throws Exception{
    //fisrt instance works OK
    DNDExample example = new DNDExample();
    example.open();

    //second instance has problems with DropTarget initialization
    //for cleaner experiment, let's use another UI thread
    Runnable runnable = new Runnable() {
        public void run() {
            DNDExample example2 = new DNDExample();
            example2.open();
        }
    };
    new Thread(runnable).start();

    Thread.sleep(Long.MAX_VALUE);
}

2. Run DNDExample, make sure example Shell is displayed.
3. Click on DropTarget check box, which causes creation of DropTarget
associated with Label control.
4. Close the Shell, which causes disposal of Label control and associated
DropTarget. When DropTarget refCount becomes 0, disposeCOMInterfaces()
method is called, which should completely release all system resources
associated with DropTarget.
5. Make sure example2 Shell instance is displayed.
6. Click on DropTarget check box, which should create another DropTarget
instance. Instead, SWT fails with stack trace provided above.