diff --git a/kifu/kifu-core/src/lib.rs b/kifu/kifu-core/src/lib.rs
index a13d2c8..9c22bc8 100644
--- a/kifu/kifu-core/src/lib.rs
+++ b/kifu/kifu-core/src/lib.rs
@@ -1,5 +1,3 @@
-use std::time::Duration;
-
 mod api;
 pub use api::{CoreApp, Request, Response};
 
diff --git a/kifu/kifu-core/src/ui/playing_field.rs b/kifu/kifu-core/src/ui/playing_field.rs
index 7398744..cdc9c12 100644
--- a/kifu/kifu-core/src/ui/playing_field.rs
+++ b/kifu/kifu-core/src/ui/playing_field.rs
@@ -1,4 +1,4 @@
-use crate::types::{Color, Size};
+use crate::types::Color;
 use crate::{types::GameState, ui::types};
 
 #[derive(Clone, Debug)]
diff --git a/kifu/kifu-gtk/src/main.rs b/kifu/kifu-gtk/src/main.rs
index d1ce77d..2ede4f3 100644
--- a/kifu/kifu-gtk/src/main.rs
+++ b/kifu/kifu-gtk/src/main.rs
@@ -1,15 +1,7 @@
-use gio::resources_lookup_data;
 use gtk::prelude::*;
 use kifu_core::{CoreApp, Request, Response};
 use kifu_gtk::{ui::PlayingField, CoreApi};
-use std::{
-    sync::{Arc, Mutex, RwLock},
-    time::Duration,
-};
-use tokio::{
-    runtime::Runtime,
-    sync::mpsc::{Receiver, Sender},
-};
+use std::sync::{Arc, RwLock};
 
 fn main() {
     gio::resources_register_include!("com.luminescent-dreams.kifu-gtk.gresource")
diff --git a/kifu/kifu-gtk/src/ui/board.rs b/kifu/kifu-gtk/src/ui/board.rs
index de9b561..4ededd6 100644
--- a/kifu/kifu-gtk/src/ui/board.rs
+++ b/kifu/kifu-gtk/src/ui/board.rs
@@ -27,7 +27,7 @@ pub struct BoardPrivate {
 
     current_player: Rc<RefCell<Color>>,
     board: Rc<RefCell<BoardElement>>,
-    cursor_location: Rc<RefCell<Addr>>,
+    cursor_location: Rc<RefCell<Option<Addr>>>,
 
     api: Rc<RefCell<Option<CoreApi>>>,
 }
@@ -135,14 +135,17 @@ impl ObjectImpl for BoardPrivate {
                 });
 
                 let cursor = cursor_location.borrow();
-                match board.stone(cursor.row, cursor.column) {
-                    IntersectionElement::Empty(_) => pen.ghost_stone(
-                        context,
-                        cursor.row,
-                        cursor.column,
-                        *current_player.borrow(),
-                    ),
-                    _ => {}
+                match *cursor {
+                    None => {}
+                    Some(ref cursor) => match board.stone(cursor.row, cursor.column) {
+                        IntersectionElement::Empty(_) => pen.ghost_stone(
+                            context,
+                            cursor.row,
+                            cursor.column,
+                            *current_player.borrow(),
+                        ),
+                        _ => {}
+                    },
                 }
                 let render_end = std::time::Instant::now();
                 println!("board rendering time: {:?}", render_end - render_start);
@@ -159,12 +162,17 @@ impl ObjectImpl for BoardPrivate {
                 let hspace_between = ((WIDTH - 40) as f64) / ((board.size.width - 1) as f64);
                 let vspace_between = ((HEIGHT - 40) as f64) / ((board.size.height - 1) as f64);
 
-                let addr = Addr {
-                    column: ((x.round() - 20.) / hspace_between).round() as u8,
-                    row: ((y.round() - 20.) / vspace_between).round() as u8,
-                };
+                let addr =
+                    if x.round() < 20. || x.round() > 780. || y.round() < 20. || y.round() > 780. {
+                        None
+                    } else {
+                        Some(Addr {
+                            column: ((x.round() - 20.) / hspace_between).round() as u8,
+                            row: ((y.round() - 20.) / vspace_between).round() as u8,
+                        })
+                    };
 
-                if *cursor != addr {
+                if *cursor != addr.clone() {
                     *cursor = addr;
                     drawing_area.queue_draw();
                 }
@@ -179,15 +187,18 @@ impl ObjectImpl for BoardPrivate {
             gesture.connect_released(move |_, _, _, _| {
                 let board = board.borrow();
                 let cursor = cursor.borrow();
-                match board.stone(cursor.row, cursor.column) {
-                    IntersectionElement::Empty(request) => {
-                        println!("need to send request: {:?}", request);
-                        api.borrow()
-                            .as_ref()
-                            .expect("API must exist")
-                            .dispatch(request);
-                    }
-                    _ => {}
+                match *cursor {
+                    None => {}
+                    Some(ref cursor) => match board.stone(cursor.row, cursor.column) {
+                        IntersectionElement::Empty(request) => {
+                            println!("need to send request: {:?}", request);
+                            api.borrow()
+                                .as_ref()
+                                .expect("API must exist")
+                                .dispatch(request);
+                        }
+                        _ => {}
+                    },
                 }
             });
         }
diff --git a/kifu/kifu-gtk/src/ui/player_card.rs b/kifu/kifu-gtk/src/ui/player_card.rs
index 04e10e2..c10012c 100644
--- a/kifu/kifu-gtk/src/ui/player_card.rs
+++ b/kifu/kifu-gtk/src/ui/player_card.rs
@@ -1,6 +1,6 @@
 use glib::Object;
 use gtk::{prelude::*, subclass::prelude::*};
-use kifu_core::{ui::PlayerCardElement, Color};
+use kifu_core::ui::PlayerCardElement;
 
 #[derive(Default)]
 pub struct PlayerCardPrivate {
diff --git a/kifu/kifu-gtk/src/ui/playing_field.rs b/kifu/kifu-gtk/src/ui/playing_field.rs
index 1738cf3..afcb93d 100644
--- a/kifu/kifu-gtk/src/ui/playing_field.rs
+++ b/kifu/kifu-gtk/src/ui/playing_field.rs
@@ -2,27 +2,9 @@ use crate::ui::{Board, Chat, PlayerCard};
 use crate::CoreApi;
 use glib::Object;
 use gtk::{prelude::*, subclass::prelude::*};
-use kifu_core::{
-    ui::{
-        BoardElement, ChatElement, IntersectionElement, PlayerCardElement, PlayingFieldView,
-        StoneElement, TextFieldElement,
-    },
-    Color, Size,
-};
+use kifu_core::ui::PlayingFieldView;
 use std::{cell::RefCell, rc::Rc};
 
-/*
-#[derive(Clone, Debug)]
-pub struct PlayingFieldView {
-    pub board: types::GobanElement,
-    pub player_card_black: types::PlayerCardElement,
-    pub player_card_white: types::PlayerCardElement,
-    pub chat: types::ChatElement,
-    pub message: types::TextFieldElement,
-    pub current_player: Color,
-}
-*/
-
 pub struct PlayingFieldPrivate {
     board: Rc<RefCell<Option<Board>>>,
     player_card_white: Rc<RefCell<Option<PlayerCard>>>,