I have been using Salix for the past couple of years and everything is working fine.
I am looking for a good free software to flash an ISO image into usb drive. I like the isodumper in Mageia, but it is not available in Salix. I installed the AppImage version of Etcher in Salix and I am able to run. However, when I select an ISO image and click on flash, I am getting an error message saying "No polkit authentication agent found. Please install a polkit authentication agent for your desktop environment of choice to continue.". See the screenshot below.

Can someone help me how to install the polkit authentication agent for XFCE in Salix? I have been using dd command to flash the USB drive with an ISO, however, formatting the USB drive after that is a pain. If I format using gparted, it does not work all the times. I have to reboot in order to format. I never had such issues with ISOdumper in Mageia.
Thanks,
Balaji.