diff --git a/src/app.c b/src/app.c
index fad1519..4d4c913 100644
--- a/src/app.c
+++ b/src/app.c
@@ -92,6 +92,9 @@ void app_draw_pixel(void *self, struct color col, int x, int y) {
 void app_draw_rect(void *self, struct color col, const struct rect *rect) {
     struct app_instance *ins = app_find(self);
     ASSERT(ins != NULL);
+    // draw into private fb
+    tex_fill_region(&ins->framebuf, col, rect);
+    // draw on public fb
     struct tex fb_tex = fb_as_tex();
     struct tex my_view = tex_view(&fb_tex, &ins->pos);
     tex_fill_region(&my_view, col, rect);
@@ -101,9 +104,12 @@ void app_draw_rect(void *self, struct color col, const struct rect *rect) {
 void app_draw_texture(void *self, const struct tex *tex, int x, int y) {
     struct app_instance *ins = app_find(self);
     ASSERT(ins != NULL);
+    struct rect src_rect = RECT_XYWH(x, y, tex->width, tex->height);
+    // draw into private fb
+    tex_blit(&ins->framebuf, tex, NULL, &src_rect);
+    // draw on public fb
     struct tex fb_tex = fb_as_tex();
     struct tex my_view = tex_view(&fb_tex, &ins->pos);
-    struct rect src_rect = RECT_XYWH(x, y, tex->width, tex->height);
     tex_blit(&my_view, tex, NULL, &src_rect);
     fb_damage_in_rect(&src_rect, &ins->pos);
 }
@@ -159,11 +165,52 @@ void app_pop(void) {
     app_stack_size--;
 }
 
+void app_translate(size_t app_idx, int dx, int dy) {
+    // TODO could optimize the uncovered
+    ASSERT(app_idx < app_stack_size);
+    struct app_instance *ins = &app_stack[app_idx];
+    struct rect uncovered = ins->pos;
+    rect_translate(&ins->pos, dx, dy);
+    struct tex fb_tex = fb_as_tex();
+    struct tex my_view = tex_view(&fb_tex, &ins->pos);
+    // TODO correct uncover order
+    tex_blit(&fb_tex, &app_background, &uncovered, &uncovered);
+    fb_damage(uncovered);
+    tex_blit(&my_view, &ins->framebuf, NULL, NULL);
+    fb_damage(ins->pos);
+}
+
 void app_key_event_listener(struct key_event event) {
     if (app_stack_size == 0) {
         return;
     }
     struct app_instance *ins = app_top();
+
+    if (event.code == KEY_ARROW_LEFT && (event.mod & KEY_MOD_SHIFT)) {
+        if (event.pressed) {
+            app_translate(app_stack_size - 1, -10, 0);
+        }
+        return;
+    }
+    if (event.code == KEY_ARROW_RIGHT && (event.mod & KEY_MOD_SHIFT)) {
+        if (event.pressed) {
+            app_translate(app_stack_size - 1, 10, 0);
+        }
+        return;
+    }
+    if (event.code == KEY_ARROW_UP && (event.mod & KEY_MOD_SHIFT)) {
+        if (event.pressed) {
+            app_translate(app_stack_size - 1, 0, -10);
+        }
+        return;
+    }
+    if (event.code == KEY_ARROW_DOWN && (event.mod & KEY_MOD_SHIFT)) {
+        if (event.pressed) {
+            app_translate(app_stack_size - 1, 0, 10);
+        }
+        return;
+    }
+
     if (ins->template->event_keyboard) {
         ins->template->event_keyboard(ins->app, event);
     }