diff --git a/src/window.c b/src/window.c
index e7b1036f..12f276a9 100644
--- a/src/window.c
+++ b/src/window.c
@@ -1617,6 +1617,8 @@ void wUnmanageWindow(WWindow *wwin, Bool restore, Bool destroyed)
 		wApplicationDeactivate(oapp);
 	}
 
+	wNETCleanupFrameExtents(wwin);
+
 	wWindowDestroy(wwin);
 	XFlush(dpy);
 }
diff --git a/src/wmspec.c b/src/wmspec.c
index 56cab826..db3526fd 100644
--- a/src/wmspec.c
+++ b/src/wmspec.c
@@ -1642,3 +1642,8 @@ void wNETFrameExtents(WWindow *wwin)
 
 	XChangeProperty(dpy, wwin->client_win, net_frame_extents, XA_CARDINAL, 32, PropModeReplace, (unsigned char *) extents, 4);
 }
+
+void wNETCleanupFrameExtents(WWindow *wwin)
+{
+	XDeleteProperty(dpy, wwin->client_win, net_frame_extents);
+}
diff --git a/src/wmspec.h b/src/wmspec.h
index 47c4c766..03376846 100644
--- a/src/wmspec.h
+++ b/src/wmspec.h
@@ -45,4 +45,5 @@ int wNETWMGetCurrentDesktopFromHint(WScreen *scr);
 char *wNETWMGetIconName(Window window);
 char *wNETWMGetWindowName(Window window);
 void wNETFrameExtents(WWindow *wwin);
+void wNETCleanupFrameExtents(WWindow *wwin);
 #endif