diff --git a/.jules/bolt.md b/.jules/bolt.md
new file mode 100644
index 0000000..5d46ba9
--- /dev/null
+++ b/.jules/bolt.md
@@ -0,0 +1,3 @@
+## 2026-01-23 - XSync vs XFlush in drw_map
+**Learning:** In X11 window managers, using XSync in frequent drawing paths (like drw_map) causes blocking round-trips to the X server, significantly degrading performance.
+**Action:** Use XFlush for drawing operations where synchronous confirmation is not required.
diff --git a/drw.c b/drw.c
index 7e99a38..66e008b 100644
--- a/drw.c
+++ b/drw.c
@@ -494,7 +494,9 @@ void drw_map(Drw *drw, Window win, int x, int y, unsigned int w,
     }
 
     XCopyArea(drw->dpy, drw->drawable, win, drw->gc, x, y, w, h, x, y);
-    XSync(drw->dpy, False);
+    /* XFlush is used here instead of XSync to avoid blocking round-trips
+     * during frequent drawing operations. */
+    XFlush(drw->dpy);
 }
 
 unsigned int drw_fontset_getwidth(Drw *drw, const char *text) {