If segmentation fault occurs, try this patch.
It works good for my environment.

diff --git a/src/main.c b/src/main.c
index 520738c..0462ddf 100644
--- a/src/main.c
+++ b/src/main.c
@@ -2363,6 +2363,7 @@ update_default_decorations(GdkScreen * screen, frame_settings * fs_act,

bareAtom = XInternAtom(xdisplay, DECOR_BARE_ATOM_NAME, FALSE);
activeAtom = XInternAtom(xdisplay, DECOR_ACTIVE_ATOM_NAME, FALSE);
+ data = decor_alloc_property (1, WINDOW_DECORATION_TYPE_PIXMAP);

if (ws->shadow_pixmap)
{
@@ -2372,7 +2373,6 @@ update_default_decorations(GdkScreen * screen, frame_settings * fs_act,

nQuad = set_shadow_quads(quads, width, height, ws);

- data = decor_alloc_property (1, WINDOW_DECORATION_TYPE_PIXMAP);

decor_quads_to_property(data, 0, GDK_PIXMAP_XID(ws->shadow_pixmap),
&ws->shadow_extents, &ws->shadow_extents, &ws->shadow_extents, &ws->shadow_extents,