YoWindow author is here.
Adobe has fixed the problem in the next BETA version of Flash Player.
Unfortunately, I don't know when they are going to release the update.
However, you can workaround the problem by installing the Flash Player BETA.
Here's how.
1. Uninstall the current Flash Player for Internet Explorer.
Download Flash Player uninstaller.
https://fpdownload.macromedia.com/pub/l ... player.exe
And run it.
2. Download Flash Player BETA for Internet Explorer.
https://fpdownload.macromedia.com/pub/l ... yer_ax.exe
And install it.
YoWindow should work just fine.
Pasha