Hi MD.Shahidul Islam Try fixing broken packages with synaptic Synaptic>Edit>Fix Broken Packages
As HayderCtee pointed out in https://trisquel.info/fr/forum/more-xfce-problems#comment-120971
Not just xfce, gnome and many other packages is broken by default in trisquel 8.0, because fildas repository is not complete, so you should download missing packages manually , some times you should download more than 20 packages( I hope Trisquel team will fix this problem )
Best to stick to default Uruk Mate environment for the moment ;-)
