Comment 2 for bug 1579723

I agree that kded should not keep continuing to prompt to install flash after it's been declined. Do note that you can work around this behavior (I believe, I'm not a kde user) as described in http://askubuntu.com/questions/616348/how-to-disable-extra-packages-can-be-installed-popup-in-kubuntu-15-04 . Thanks for your report!