A user reported on the Java Plug-In forum that modal dialogs are occasionally not behaving properly with the new Java Plug-In, resulting in UI issues such as combo boxes not appearing. The test case is attached. This is probably due to the rewritten nested message pump used both during JavaScript-to-Java calls as well as when modal dialogs are active. This code has undergone several iterations in 6647406, 6619480, and 6642444. It has proven somewhat tricky to get right under multiple compatibility constraints while still keeping it simple and browser-independent.

To reproduce the failures, compile the test case and load the HTML file in IE (has been reproduced with 7). Click the button to pop up the modal dialog and then click in the browser window's area. The modal dialog will be reactivated with a beep and flash. At that point, try to drop down the combo box. Occasionally it will fail to appear. You may need to click around the browser window a few times. It isn't clear whether the problem is reproducible with Firefox 3. It may be related to the threading model of the IE 7 browser and the fact that we don't and/or can't block all of the browser's GUI operations because some of them occur on different threads.

The forum thread under on which this problem was reported is http://forums.java.net/jive/thread.jspa?threadID=38577&tstart=0 .