TitleWindow that contains ProgressBar doesn't show up in IE if you download same file twice or more.

TitleWindow that contains ProgressBar and is modal doesn't show up until right before the complete event fires in IE if you download same file twice or more, that is, if the file is cached by IE. This problem cannot reproduce in Firefox and Chrome. It can reproduce with Flex SDK 2.0.1 or later (including 4.5.0.20834). And it occurs with Spark TitleWindow as well.

Steps to reproduce:
1. Prepare a large size file over 100MB and put it on your web server.
2. Run "Main.mxml" with Internet Explorer.
3. Input the URL on which you put the file.
4. Click 'Download' button and select a location where you want to save it.
5. You will see ProgressBar while downloading the file.
6. After the download has completed, click 'Download' button again and select the same location as in step 3.

Actual Results:
TitleWindow doesn't show up until right before the complete event fires.

Expected Results:
TitleWindow should show up right after calling createPopup() method.

Workaround (if any):
Append a random string as a query string to the URL so as not to have IE use the cache.