--- copy-dwm.c	2012-11-19 23:07:38.406816000 +0530
+++ dwm.c	2012-11-19 23:36:52.259389209 +0530
@@ -87,7 +87,7 @@
 enum { CurNormal, CurResize, CurMove, CurLast };        /* cursor */
 enum { ColBorder, ColFG, ColBG, ColLast };              /* color */
 enum { NetSupported, NetSystemTray, NetSystemTrayOP, NetSystemTrayOrientation,
-	   NetWMName, NetWMState, NetWMFullscreen, NetActiveWindow, NetWMWindowType,
+	   NetWMName, NetWMState, NetWMFullscreen, NetWMWindowsOpacity, NetActiveWindow, NetWMWindowType,
 	   NetWMWindowTypeDialog, NetLast }; /* EWMH atoms */
 enum { Manager, Xembed, XembedInfo, XLast }; /* Xembed atoms */
 enum { WMProtocols, WMDelete, WMState, WMTakeFocus, WMLast }; /* default atoms */
@@ -1849,6 +1849,7 @@ setup(void) {
 	xatom[Manager] = XInternAtom(dpy, "MANAGER", False);
 	xatom[Xembed] = XInternAtom(dpy, "_XEMBED", False);
 	xatom[XembedInfo] = XInternAtom(dpy, "_XEMBED_INFO", False);
+	netatom[NetWMWindowsOpacity] = XInternAtom(dpy, "_NET_WM_WINDOW_OPACITY", False);
 	/* init cursors */
 	cursor[CurNormal] = XCreateFontCursor(dpy, XC_left_ptr);
 	cursor[CurResize] = XCreateFontCursor(dpy, XC_sizing);
@@ -2133,6 +2134,10 @@ updatebars(void) {
 		m->barwin = XCreateWindow(dpy, root, m->wx, m->by, w, bh, 0, DefaultDepth(dpy, screen),
 		                          CopyFromParent, DefaultVisual(dpy, screen),
 		                          CWOverrideRedirect|CWBackPixmap|CWEventMask, &wa);
+		unsigned long real_opacity[] = { opacity * 0xffffffff };
+		XChangeProperty(dpy, m->barwin, netatom[NetWMWindowsOpacity], XA_CARDINAL,
+				32, PropModeReplace, (unsigned char *)real_opacity,
+				1);
 		XDefineCursor(dpy, m->barwin, cursor[CurNormal]);
 		XMapRaised(dpy, m->barwin);
 	}