Comment 3 for bug 87583

I can confirm this is a problem in Feisty, it just happened to me, placing a 4 of hearts on top of a 2 of hearts, and making the game unwinnable if you don't notice what it's done.

There is a bug filed on this on the KDE Bugzilla (http://bugs.kde.org/show_bug.cgi?id=56637), and there's a patch posted on 29/10/2006 which supposedly fixes the issue.

I don't know whether that patch was in Sid when the Feisty tree was downloaded.