Bug 220767 [Dialogs] PopupDialog's HOVER_SHELLSTYLE should use SWT.TOOL
3.3.x and 3.4 M5. The SWT.TOOL flag should be used to create hover style shells, hence the PopupDialog's HOVER_SHELLSTYLE should use SWT.TOOL.
bundles/org.eclipse.jface/src/org/eclipse/jface/dialogs/PopupDialog.java
* It never blocks on open, immediately returning <code>OK</code> if the
	 * open is successful, or <code>CANCEL</code> if it is not. It provides
	 * framework hooks that allow subclasses to set the focus and tab order, and
	 * avoids the use of <code>shell.open()</code> in cases where the focus
	 * should not be given to the shell initially.
	 * 
	 * @return the return code
	 * 
	 * @see org.eclipse.jface.window.Window#open()
	 */
	public int open() {
		Shell shell = getShell();
		if (shell == null || shell.isDisposed()) {
			shell = null;
			
			create();
			shell = getShell();
		}
		
		
		
		adjustBounds();
		
		constrainShellSize();
		
		setTabOrder((Composite) getContents());
		
		listenToDeactivate = false;
		listenToParentDeactivate = false;