
It should be allowed to set this._spacing to 0 and thus pass 0 as rowSpacing or colSpacing to this._adjustSpacingAndPadding(). The current if-condition there won't add the oversize to the spacing in case 0 is passed though. So change that if-condition and explicitely check for null instead. Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1698>