So, a quick
sudo mv /usr/lib/xfce4/panel/plugins/libhotcorner.so /usr/lib64/xfce4/panel/plugins/libhotcorner.soresolves this problem.
P.S.: There seems to be a problem with the fixation of the "Custom Command" you can put in. For me this command would be skippy-xd --activate-window-picker to activate the window manager tool Skippy (openSUSE download). The custom command is working fine in HotCorner but sometimes when opening the properties dialogue again the setting is gone and the configuration file ~/.config/xfce4/panel/hotcorner-17.rc does not contain the custom command setting any more.