The following code will cause the problem:
var titleWindow:TitleWindow = new TitleWindow(); titleWindow.width = 500; titleWindow.height = 500; titleWindow.title= "test"; PopUpManager.addPopUp(titleWindow, parent, true); PopUpManager.centerPopUp(titleWindow);
The modal blurring appears, but no popup.
If you wait an unreasonable amount of time 5-10 seconds, it may appear. Otherwise, if I force the window to redraw by switching tabs or resize, the popup appears immediately.
This issue appeared when updating from Flash Player 11 to Flash Player 12.