WINGs: commit all mapped toplevels on every event loop flush

Widgets that paint directly to their view backing (fill_rect,
draw_line, W_DrawRelief, W_PaintText) without going through the
DOUBLE_BUFFER pixmap_copy path never triggered a surface commit.
The painted content stayed in the pixman buffer but was never
submitted to the compositor — making popup menus, radio buttons,
text fields, sliders, and other controls appear empty/stale.

Fix: W_WLClientCommitAllToplevels() iterates all mapped toplevels
and commits their surfaces. Called from wl_flush() which runs once
per event loop iteration (in waitForEvent). This ensures any
direct-paint operations become visible on the next frame regardless
of which render path was used.

WINGs/wclient_wl.c

@@ -584,6 +584,22 @@ W_WLClientBeginMove(WNativeWindow window)
     return True;
 }
 
+/* ------------------------------------------------------------------ */
+
+void
+W_WLClientCommitAllToplevels(void)
+{
+    for (int i = 0; i < WLC_TOPTABLE_SIZE; i++) {
+        WLClientToplevel *top = wlc_toptable[i].top;
+        if (top && top->mapped && top->configured && top->buf && top->buf->wl_buf) {
+            wl_surface_attach(top->surface, top->buf->wl_buf, 0, 0);
+            wl_surface_damage_buffer(top->surface, 0, 0,
+                                     top->buf->width, top->buf->height);
+            wl_surface_commit(top->surface);
+        }
+    }
+}
+
 /* ------------------------------------------------------------------ */
 /* Input: wl_pointer / wl_keyboard listeners                          */
 /* ------------------------------------------------------------------ */

WINGs/wevent_wl.c

@@ -157,11 +157,17 @@ wl_check_typed_window(void *ectx, WNativeWindow w, int type, WMEvent *ev)
     return False;
 }
 
+extern void W_WLClientCommitAllToplevels(void);
+
 static void
 wl_flush(void *ectx, Bool discard)
 {
     WLEventCtx *ctx = ectx;
     (void)discard;
+    /* Commit any toplevel surfaces that may have been painted into
+     * since the last flush (direct fill_rect, draw_line, etc. don't
+     * trigger individual commits). */
+    W_WLClientCommitAllToplevels();
     /* Pump the wlroots event loop so pointer/key events arrive in our queue.
      * This is called from waitForEvent/WMMaskEvent when the queue is empty. */
     if (ctx->dispatch_fn)