diff --git a/simu/src/cpu.rs b/simu/src/cpu.rs
index 7fde276..9594f20 100644
--- a/simu/src/cpu.rs
+++ b/simu/src/cpu.rs
@@ -508,7 +508,11 @@ impl Computer {
                             self.ram[addr / 4] = self[reg1];
                         } else if addr <= 0x00ff_ffff + 480 * 640 * 4 {
                             let buf_addr = (addr - 0x0100_0000) / 4;
-                            let dat = self[reg1] & 0x00FF_FFFF;
+                            let dat = if cfg!(feature = "rgba") {
+                                self[reg1]
+                            } else {
+                                self[reg1] & 0x00FF_FFFF
+                            };
                             (&SHARED.screen_buf[buf_addr])
                                 .store(dat, std::sync::atomic::Ordering::Relaxed);
                         } else if addr == 0x0120_1000 {
diff --git a/simu/src/main.rs b/simu/src/main.rs
index 068d76d..3cbd095 100644
--- a/simu/src/main.rs
+++ b/simu/src/main.rs
@@ -21,7 +21,6 @@ use winit::application::ApplicationHandler;
 use winit::dpi::LogicalSize;
 use winit::event::WindowEvent;
 use winit::event_loop::EventLoop;
-use winit::platform::modifier_supplement::KeyEventExtModifierSupplement;
 use winit::platform::scancode::PhysicalKeyExtScancode;
 use winit::window::Window;
 
@@ -59,7 +58,8 @@ impl<'a> ApplicationHandler for App<'a> {
                         Window::default_attributes()
                             .with_title("bisare screen")
                             .with_min_inner_size(size)
-                            .with_maximized(true),
+                            .with_maximized(true)
+                            .with_transparent(true),
                     )
                     .unwrap(),
             )
@@ -92,6 +92,7 @@ impl<'a> ApplicationHandler for App<'a> {
                 print!("Keyboard event: ");
                 #[cfg(feature = "rich_keyboard")]
                 {
+                    use winit::platform::modifier_supplement::KeyEventExtModifierSupplement;
                     let kb0 = key_event.text_with_all_modifiers().map_or(u32::MAX, |s| {
                         s.as_bytes()
                             .into_iter()