diff --git a/.jules/bolt.md b/.jules/bolt.md
new file mode 100644
index 0000000..130a3e9
--- /dev/null
+++ b/.jules/bolt.md
@@ -0,0 +1,4 @@
+
+## 2026-02-03 - XSync in Drawing Loops
+**Learning:** `XSync` forces a blocking round-trip to the X server, which is catastrophic for performance in frequently called drawing functions like `drw_map`.
+**Action:** Replace `XSync` with `XFlush` in drawing routines where strict synchronization is not required.
diff --git a/drw.c b/drw.c
index 7e99a38..35362fc 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);
+    /* Performance: XFlush is sufficient here; XSync causes unnecessary blocking
+     * round-trips. */
+    XFlush(drw->dpy);
 }
 
 unsigned int drw_fontset_getwidth(Drw *drw, const char *text) {