It seems that several packages in 14.1 are not quite ready for prime time.
upower doesn't deal with the rearrangement of usb-hid devices in /sys/class. The problem is in the udev files in the package, not the code. The latest source on the web is OK, but the slackpkg is a couple of revisions older.
GTK-3 doesn't draw non-sensitive buttons correctly.
But the biggest problem seems to be with the new (version 14) xorg-server. There was a big push for xcb...