When you start kickshaw on terminal what does it do? Mine works fine.
What does your ~/.kickshawrc looks like?
% more .kickshawrc
# Generated by Kickshaw GTK3 1.0.43
[VIEW]
sf-showmenuidcol=true
sf-showexecutecol=true
sf-showicons=true
sf-setoffsep=true
sf-showtreelines=true
sf-elmviscol=false
sf-highlightingstate=true
sf-gridstate=no_grid_lines
[OPTIONS]
sf-createbackup=true
sf-usetabs=true
sf-separaterootmenu=true
sf-sortoptions=false
sf-notifyaboutconversions=true
sf-useheaderbar=false
sf-showmenubutton=true
% mv ~/.kickshawrc ~/.kickshawrc.tmp
then copy the above contents into a new ~/.kickshawrc
and try it.
If not maybe gtk3 is messed up, have you substituted gtk3 with one from AUR?
% sudo pacman -Rdd gtk3
% sudo pacman -S gtk3