It seems your Window Manager (e.g. xfwm4) or your composite manager (e.g. Compton, xcompmgr, etc.) add some shadows around Cairo-Dock's windows. They shouldn't add any shadows around windows of type "Dock" (_NET_WM_WINDOW_TYPE_DOCK).
Can you have a look to your Window Manager or Composite Manager' settings and check if it's possible to disable this feature for windows of type DOCK? If not, please report this bug to the devs of your Window Manager or Composite Manager. By default, they should add shadows for this windows' type.
Hello and sorry for the delay!
It seems your Window Manager (e.g. xfwm4) or your composite manager (e.g. Compton, xcompmgr, etc.) add some shadows around Cairo-Dock's windows. They shouldn't add any shadows around windows of type "Dock" (_NET_WM_ WINDOW_ TYPE_DOCK) .
Can you have a look to your Window Manager or Composite Manager' settings and check if it's possible to disable this feature for windows of type DOCK? If not, please report this bug to the devs of your Window Manager or Composite Manager. By default, they should add shadows for this windows' type.