Index: uspace/lib/ui/test/rbutton.c
===================================================================
--- uspace/lib/ui/test/rbutton.c	(revision 9c7dc8e93da9abc90efb24bba56e275432050f20)
+++ uspace/lib/ui/test/rbutton.c	(revision 1aa0e380b50a49fcd7536c60dde5800c2965e6ce)
@@ -43,4 +43,5 @@
 static errno_t testgc_set_color(void *, gfx_color_t *);
 static errno_t testgc_fill_rect(void *, gfx_rect_t *);
+static errno_t testgc_update(void *);
 static errno_t testgc_bitmap_create(void *, gfx_bitmap_params_t *,
     gfx_bitmap_alloc_t *, void **);
@@ -52,4 +53,5 @@
 	.set_color = testgc_set_color,
 	.fill_rect = testgc_fill_rect,
+	.update = testgc_update,
 	.bitmap_create = testgc_bitmap_create,
 	.bitmap_destroy = testgc_bitmap_destroy,
@@ -564,4 +566,10 @@
 	(void) arg;
 	(void) rect;
+	return EOK;
+}
+
+static errno_t testgc_update(void *arg)
+{
+	(void) arg;
 	return EOK;
 }