diff --git a/build_file.c b/build_file.c
index 4ea8a5c..f341d0b 100644
--- a/build_file.c
+++ b/build_file.c
@@ -38,8 +38,8 @@ int main(int argc, char **argv) {
     mt_testing(tcx->temp);
 
     b32 run_server = false;
-    b32 core_test_target = true;
-    b32 win32_target = false;
+    b32 core_test_target = false;
+    b32 win32_target = true;
     b32 standalone_w32_target = false;
     b32 wasm_target = false;
 
diff --git a/src/app/app_win32.c b/src/app/app_win32.c
index f484848..89743c6 100644
--- a/src/app/app_win32.c
+++ b/src/app/app_win32.c
@@ -1,4 +1,6 @@
+#include "os/os.h"
 #include "app_win32_opengl.c"
+#include "os/os.c"
 
 #pragma comment(linker, "/subsystem:windows")
 #pragma comment(lib, "gdi32.lib")
@@ -288,7 +290,7 @@ fn void w32_set_event(app_frame_t *frame, app_event_t ev) {
 }
 
 fn void w32_try_reloading_library(w32_library_t *lib, app_frame_t frame) {
-    i64 new_write_time = os_get_file_mod_time(lib->dll_name);
+    i64 new_write_time = os_mod_time(lib->dll_name);
     if (new_write_time == -1 || new_write_time == lib->last_write_time) {
         goto end_of_lib_load;
     }
@@ -347,7 +349,7 @@ int WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int n
     {
         ma_temp_t scratch = ma_begin_scratch();
         s8_t dir = os_exe_dir(scratch.arena);
-        for (os_file_iter_t *it = os_iterate_files(scratch.arena, dir); it->is_valid; os_advance(it)) {
+        for (os_iter_t *it = os_iter(scratch.arena, dir); it->is_valid; os_advance(it)) {
             b32 is_dll = s8_ends_with(it->name, s8_lit(".dll"), false);
             b32 is_pdb = s8_ends_with(it->name, s8_lit(".pdb"), false);
             b32 is_rdi = s8_ends_with(it->name, s8_lit(".rdi"), false);
diff --git a/src/os/os.c b/src/os/os.c
index 545a1d1..a4d622f 100644
--- a/src/os/os.c
+++ b/src/os/os.c
@@ -6,26 +6,7 @@
 #include "os_unix.c"
 #endif
 
-
-fn_test void os_test(void) {
-    os_date_t local_time = os_local_time();
-    os_date_t universal_time = os_universal_time();
-    debugf("local_time = %S | universal_time = %S", os_format_date(tcx->temp, local_time), os_format_date(tcx->temp, universal_time));
-
-    s8_t exe_dir = os_exe_dir(tcx->temp);
-    assert(exe_dir.str[exe_dir.len - 1] == '/');
-    s8_t exe     = os_exe(tcx->temp);
-    s8_t cwd     = os_cwd(tcx->temp);
-    assert(exe_dir.str[cwd.len - 1] == '/');
-    assert(os_is_dir(exe_dir));
-    assert(os_is_file(exe));
-    assert(os_is_dir(cwd));
-    assert(os_exists(exe_dir));
-    assert(os_exists(exe));
-    assert(os_exists(cwd));
-    assert(os_is_abs(exe_dir));
-    assert(os_is_abs(exe));
-    assert(os_is_abs(cwd));
-    assert(!os_is_abs(s8_lit("../path/")));
-    debugf("%S %S %S", exe_dir, exe, cwd);
+fn s8_t os_format_date(ma_arena_t *arena, os_date_t date) {
+    s8_t result = s8_printf(arena, "%04u-%02u-%02u %02u:%02u:%02u.%03u", date.year, date.month, date.day, date.hour, date.min, date.sec, date.ms);
+    return result;
 }
diff --git a/src/os/os_win32.c b/src/os/os_win32.c
index 361b110..974ff1d 100644
--- a/src/os/os_win32.c
+++ b/src/os/os_win32.c
@@ -28,11 +28,6 @@ fn os_date_t os_universal_time(void) {
     return result;
 }
 
-fn s8_t os_format_date(ma_arena_t *arena, os_date_t date) {
-    s8_t result = s8_printf(arena, "%04u-%02u-%02u %02u:%02u:%02u.%03u", date.year, date.month, date.day, date.hour, date.min, date.sec, date.ms);
-    return result;
-}
-
 fn f64 os_seconds(void) {
     static int64_t counts_per_second;
     if (counts_per_second == 0) {
@@ -303,7 +298,7 @@ fn os_thread_t os_thread_create(ma_arena_t *arena, os_thread_fn_t *func, void *u
     return result;
 }
 
-fn i32 os_join(os_thread_t *thread) {
+fn i32 os_thread_join(os_thread_t *thread) {
     DWORD return_value_indicates_event = WaitForSingleObject(thread->w32->handle, INFINITE);
     if (return_value_indicates_event != WAIT_OBJECT_0) {
         debugf(__FUNCTION__".WaitForSingleObject failed: %d", GetLastError());
@@ -337,7 +332,7 @@ fn i32 os_join(os_thread_t *thread) {
 //         threads[i] = os_thread_create(scratch.arena, os__thread_log, NULL);
 //     }
 //     for (int i = 0; i < lengthof(threads); i += 1) {
-//         os_join(&threads[i]);
+//         os_thread_join(&threads[i]);
 //     }
 //     ma_end_scratch(scratch);
 // }
\ No newline at end of file
diff --git a/src/testing/testing.gen.c b/src/testing/testing.gen.c
index 7aac4d5..3794dc6 100644
--- a/src/testing/testing.gen.c
+++ b/src/testing/testing.gen.c
@@ -2,5 +2,4 @@ fn void run_tests(void) {
     test_s8();
     test_hash_table();
     test_intern_table();
-    os_test();
 }
diff --git a/src/testing/testing_main.c b/src/testing/testing_main.c
index 63a2d02..211faf2 100644
--- a/src/testing/testing_main.c
+++ b/src/testing/testing_main.c
@@ -5,8 +5,32 @@
 
 #include "testing.gen.c"
 
+fn void os_test(void) {
+    os_date_t local_time = os_local_time();
+    os_date_t universal_time = os_universal_time();
+    debugf("local_time = %S | universal_time = %S", os_format_date(tcx->temp, local_time), os_format_date(tcx->temp, universal_time));
+
+    s8_t exe_dir = os_exe_dir(tcx->temp);
+    assert(exe_dir.str[exe_dir.len - 1] == '/');
+    s8_t exe     = os_exe(tcx->temp);
+    s8_t cwd     = os_cwd(tcx->temp);
+    assert(exe_dir.str[cwd.len - 1] == '/');
+    assert(os_is_dir(exe_dir));
+    assert(os_is_file(exe));
+    assert(os_is_dir(cwd));
+    assert(os_exists(exe_dir));
+    assert(os_exists(exe));
+    assert(os_exists(cwd));
+    assert(os_is_abs(exe_dir));
+    assert(os_is_abs(exe));
+    assert(os_is_abs(cwd));
+    assert(!os_is_abs(s8_lit("../path/")));
+    debugf("%S %S %S", exe_dir, exe, cwd);
+}
+
 int main() {
     core_init();
     run_tests();
+    os_test();
     return 0;
 }
\ No newline at end of file
diff --git a/src/ui/ui.c b/src/ui/ui.c
index 85f27a1..2f48973 100644
--- a/src/ui/ui.c
+++ b/src/ui/ui.c
@@ -387,17 +387,21 @@ struct ui_draw_compute_t {
     v4f32_t text_color;
 };
 
+fn r2f32_t ui_get_appear_rect(ui_box_t *box) {
+    r2f32_t result = box->rect;
+    f32 appear_t = f32_ease_out_n(f32_clamp01(box->appear_t * 2), 10);
+    if (!ui_id_is_null(box->id)) {
+        v2f32_t size = v2f32_muls(r2f32_get_size(result), 0.15f);
+        r2f32_t smaller_rect = r2f32_shrink(result, size);
+        result = r2f32_lerp(smaller_rect, result, appear_t);
+    }
+    return result;
+}
+
 fn ui_draw_compute_t ui_draw_compute(ui_box_t *box) {
     ui_draw_compute_t co = {0};
 
-    co.rect = box->rect;
-    f32 appear_t = f32_ease_out_n(f32_clamp01(box->appear_t * 2), 10);
-    if (!ui_id_is_null(box->id)) {
-        v2f32_t size = v2f32_muls(r2f32_get_size(co.rect), 0.15f);
-        r2f32_t smaller_rect = r2f32_shrink(co.rect, size);
-        co.rect = r2f32_lerp(smaller_rect, co.rect, appear_t);
-    }
-
+    co.rect = ui_get_appear_rect(box);
     co.background_color = box->background_color;
     co.text_color = box->text_color;
     co.border_color = box->border_color;
@@ -964,6 +968,7 @@ struct ui_scroller_params_t {
         b8 enabled;
         f32 *value;
         f32 max_size;
+        ui_code_loc_t loc;
     } hori;
     struct {
         b8 enabled;
@@ -973,6 +978,7 @@ struct ui_scroller_params_t {
         i32 item_count;
         // @option2: non efficient
         f32 max_size;
+        ui_code_loc_t loc;
     } verti;
 };
 
@@ -990,11 +996,11 @@ struct ui_scroller_t {
     ui_scroller_params_t p;
 };
 
-fn ui_scroller_t ui_begin_scroller(ui_scroller_params_t p) {
+fn ui_scroller_t ui_begin_scroller(ui_code_loc_t loc, ui_scroller_params_t p) {
     ui_scroller_t r = {.p = p};
 
     if (p.verti.enabled) {
-        r.verti.box = ui_box(.rect = r2f32_cut_right(&p.parent->rect, ui_dm(0.5f)), .flags = {.draw_rect = true});
+        r.verti.box = ui_box(.loc = loc, .rect = r2f32_cut_right(&p.parent->rect, ui_dm(0.5f)), .flags = {.draw_rect = true});
         r2f32_cut_bottom(&r.verti.box->rect, ui_dm(0.5f));
         r.verti.item_box_pixels = r2f32_get_size(p.parent->rect).y;
 
@@ -1011,7 +1017,8 @@ fn ui_scroller_t ui_begin_scroller(ui_scroller_params_t p) {
     }
 
     if (p.hori.enabled) {
-        r.hori.box = ui_box(.rect = r2f32_cut_bottom(&p.parent->rect, ui_dm(0.5f)), .flags = {.draw_rect = true});
+        loc.counter += 10000;
+        r.hori.box = ui_box(.loc = loc, .rect = r2f32_cut_bottom(&p.parent->rect, ui_dm(0.5f)), .flags = {.draw_rect = true});
     }
 
     return r;
@@ -1157,7 +1164,8 @@ fn void ui__draw_box(app_frame_t *frame, ui_box_t *box) {
 
     r2f32_t prev_clip_rect = ui->clip_rect;
     if (box->flags.clip_rect) {
-        ui->clip_rect = r2f32_intersect(ui->clip_rect, box->rect);
+        r2f32_t rect = ui_get_appear_rect(box);
+        ui->clip_rect = r2f32_intersect(ui->clip_rect, rect);
         rn_set_clip(ui->clip_rect);
     }
     for (ui_box_t *it = box->first; it; it = it->next) {
@@ -1184,7 +1192,11 @@ fn void ui_begin_frame(app_frame_t *frame) {
 fn void ui_end_frame(void) {
     for (ui_box_t *box = ui->hash_first, *next = NULL; box; box = next) {
         next = box->hash_next;
-        box->appear_t += (f32)ui->frame->delta;
+        // if (box->flags.animate_appear) {
+            box->appear_t += (f32)ui->frame->delta;
+        // } else {
+        //     box->appear_t = 1;
+        // }
         if (ui_is_hot_box(box)) {
             box->hot_t += (f32)ui->frame->delta;
         } else {
@@ -1249,7 +1261,7 @@ fn void ui_demo_update(app_frame_t *frame, mt_tweak_t *tweak_table, i32 tweak_co
             ui_box_t *item_box = ui_box(r2f32_cut_left(ui_top_rectp(), ui_max), {.draw_rect = true, .clip_rect = true});
 
             static f32 verti_scroller_value;
-            ui_scroller_t scroller = ui_begin_scroller((ui_scroller_params_t){
+            ui_scroller_t scroller = ui_begin_scroller(UILOC, (ui_scroller_params_t){
                 .parent = item_box,
                 .verti = {
                     .enabled = true,
@@ -1437,7 +1449,7 @@ fn void ui_demo_update(app_frame_t *frame, mt_tweak_t *tweak_table, i32 tweak_co
 
             locl f32 right_scroller_value;
             locl f32 bottom_scroller_value;
-            ui_scroller_t scroller = ui_begin_scroller((ui_scroller_params_t){
+            ui_scroller_t scroller = ui_begin_scroller(UILOC, (ui_scroller_params_t){
                 .parent = item_box,
                 .verti = {
                     .enabled = true,
@@ -1521,32 +1533,6 @@ fn void ui_demo_update(app_frame_t *frame, mt_tweak_t *tweak_table, i32 tweak_co
             s8_lit("show data tab"),
             s8_lit("show log tab"),
             s8_lit("show menus tab"),
-            s8_lit("x"),
-            s8_lit("x1"),
-            s8_lit("x2"),
-            s8_lit("x3"),
-            s8_lit("x4"),
-            s8_lit("x5"),
-            s8_lit("x6"),
-            s8_lit("x7"),
-            s8_lit("x8"),
-            s8_lit("x9"),
-            s8_lit("x0"),
-            s8_lit("x22"),
-            s8_lit("x33"),
-            s8_lit("x44"),
-            s8_lit("x55"),
-            s8_lit("x66"),
-            s8_lit("x77"),
-            s8_lit("x88"),
-            s8_lit("x99"),
-            s8_lit("x123"),
-            s8_lit("x12"),
-            s8_lit("x32"),
-            s8_lit("x42"),
-            s8_lit("x52"),
-            s8_lit("x64"),
-            s8_lit("x75"),
         };
 
         if (lister_open) {
@@ -1556,10 +1542,10 @@ fn void ui_demo_update(app_frame_t *frame, mt_tweak_t *tweak_table, i32 tweak_co
             v2f32_t pos = v2f32_divs(v2f32_sub(frame->window_size, lister_size), 2.0);
             pos.y *= 0.05f;
             r2f32_t rect = r2f32_min_dim(pos, lister_size);
-            ui_box_t *lister = ui_box(.id = lister_id, .rect = rect, .flags = {.draw_rect = true, .draw_border = true, .clip_rect = true});
+            ui_box_t *lister = ui_box(.id = lister_id, .rect = rect, .flags = {.animate_appear = true, .draw_rect = true, .draw_border = true, .clip_rect = true});
 
             locl f32 verti_scroller_value;
-            ui_scroller_t scroller = ui_begin_scroller((ui_scroller_params_t){
+            ui_scroller_t scroller = ui_begin_scroller(UILOC, (ui_scroller_params_t){
                 .parent = lister,
                 .verti = {
                     .enabled = true,
diff --git a/src/ui/ui.h b/src/ui/ui.h
index 766a97b..2550818 100644
--- a/src/ui/ui.h
+++ b/src/ui/ui.h
@@ -17,6 +17,8 @@ struct ui_box_flags_t {
     b8 draw_text: 1;
     b8 clip_rect: 1;
 
+    b8 animate_appear: 1;
+
     b8 children_sum_x: 1;
     b8 children_sum_y: 1;
     b8 keyboard_nav: 1;
diff --git a/todo.txt b/todo.txt
index c9f0d02..112d61f 100644
--- a/todo.txt
+++ b/todo.txt
@@ -12,7 +12,7 @@
 [ ] os
     [x] delete all pdbs\dlls on start
     [?] wasm (explore)
-    [ ] win32
+    [x] win32
     [ ] linux
 
 [ ] render