Kde panel shadow: a little problem

Hi guys! Just a question! I’m running OS 11.4 with kde and the default desktop theme Air Open Suse. Yesterday I noticed (I dont remember if it was the same before) that the shadow above the panel in the area of the kick off app starter is not visible: to be clearer, the whole panel drops a shadow on the wallpaper correctly, except for the area above kick-off app launcher, i.e. the kde menu, in which the shadow just disappears, is not present. I tried to reboot, but nothing happened. What do u think could the problem be? Should I try to restart the panel? In this case, which is the panel binary (like gnome-panel in gnome, to be clear)?

Thanks in advance!

Guys the problem is the theme Air for OpenSuse itself. I solved changing it to normal Air.