TreeEditor crash bug

[Simen Haugen]

Here's a small example that quits with a long stacktrace. I'm using dmd 
1.030, tango rev. 3543 and dwt rev. 233 on WinXP SP2


import dwt.DWT;
import dwt.layout.FillLayout;
import dwt.widgets.Display;
import dwt.widgets.Shell;
import dwt.widgets.Tree;
import dwt.custom.TreeEditor;

void main()
{
 auto display = new Display;
 auto shell = new Shell(display, DWT.NONE);
 shell.setLayout(new FillLayout());
 auto tree = new Tree(shell, DWT.NONE);
 auto ed = new TreeEditor(tree); // Remove this line to avoid crash

 shell.open(); // Crashes here
 while( !shell.isDisposed() )
 {
  if( !display.readAndDispatch() )
   display.sleep();
 }
}