diff --git a/src/lib.rs b/src/lib.rs
index 7d81677..0d9170a 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -33,7 +33,8 @@ mod title;
 mod wl_typed;
 
 use crate::theme::{
-    ColorMap, ColorTheme, BORDER_SIZE, CORNER_RADIUS, HEADER_SIZE, VISIBLE_BORDER_SIZE,
+    ColorMap, ColorTheme, BORDER_SIZE, CORNER_RADIUS, HEADER_SIZE, RESIZE_HANDLE_CORNER_SIZE,
+    VISIBLE_BORDER_SIZE,
 };
 
 use buttons::Buttons;
@@ -134,27 +135,58 @@ where
         self.dirty = true;
     }
 
-    fn precise_location(&self, location: Location, header_width: u32, x: f64, y: f64) -> Location {
+    fn precise_location(
+        &self,
+        location: Location,
+        decoration: &DecorationParts,
+        x: f64,
+        y: f64,
+    ) -> Location {
+        let header_width = decoration.header().width;
+        let side_height = decoration.side_height();
+
+        let left_corner_x = BORDER_SIZE + RESIZE_HANDLE_CORNER_SIZE;
+        let right_corner_x = (header_width + BORDER_SIZE).saturating_sub(RESIZE_HANDLE_CORNER_SIZE);
+        let top_corner_y = RESIZE_HANDLE_CORNER_SIZE;
+        let bottom_corner_y = side_height.saturating_sub(RESIZE_HANDLE_CORNER_SIZE);
         match location {
             Location::Head | Location::Button(_) => self.buttons.find_button(x, y),
             Location::Top | Location::TopLeft | Location::TopRight => {
-                if x <= f64::from(BORDER_SIZE) {
+                if x <= f64::from(left_corner_x) {
                     Location::TopLeft
-                } else if x >= f64::from(header_width + BORDER_SIZE) {
+                } else if x >= f64::from(right_corner_x) {
                     Location::TopRight
                 } else {
                     Location::Top
                 }
             }
             Location::Bottom | Location::BottomLeft | Location::BottomRight => {
-                if x <= f64::from(BORDER_SIZE) {
+                if x <= f64::from(left_corner_x) {
                     Location::BottomLeft
-                } else if x >= f64::from(header_width + BORDER_SIZE) {
+                } else if x >= f64::from(right_corner_x) {
                     Location::BottomRight
                 } else {
                     Location::Bottom
                 }
             }
+            Location::Left => {
+                if y <= f64::from(top_corner_y) {
+                    Location::TopLeft
+                } else if y >= f64::from(bottom_corner_y) {
+                    Location::BottomLeft
+                } else {
+                    Location::Left
+                }
+            }
+            Location::Right => {
+                if y <= f64::from(top_corner_y) {
+                    Location::TopRight
+                } else if y >= f64::from(bottom_corner_y) {
+                    Location::BottomRight
+                } else {
+                    Location::Right
+                }
+            }
             other => other,
         }
     }
@@ -454,10 +486,9 @@ where
             return None;
         }
 
-        let header_width = decorations.header().width;
         let old_location = self.mouse.location;
 
-        let location = self.precise_location(location, header_width, x, y);
+        let location = self.precise_location(location, decorations, x, y);
         let new_cursor = self.mouse.moved(location, x, y, self.resizable);
 
         // Set dirty if we moved the cursor between the buttons.
diff --git a/src/parts.rs b/src/parts.rs
index 2eb783b..ee20769 100644
--- a/src/parts.rs
+++ b/src/parts.rs
@@ -126,6 +126,10 @@ impl DecorationParts {
         &self.parts[Self::HEADER]
     }
 
+    pub fn side_height(&self) -> u32 {
+        self.parts[Self::LEFT].height
+    }
+
     pub fn find_surface(&self, surface: &ObjectId) -> Location {
         let pos = match self
             .parts
diff --git a/src/theme.rs b/src/theme.rs
index 1923855..f89af74 100644
--- a/src/theme.rs
+++ b/src/theme.rs
@@ -1,7 +1,11 @@
 pub use tiny_skia::Color;
 use tiny_skia::{Paint, Shader};
 
-pub(crate) const BORDER_SIZE: u32 = 10;
+// https://gitlab.gnome.org/GNOME/gtk/-/blob/1bf88f1d81043fd99740e2f91e56ade7ede7303b/gtk/gtkwindow.c#L165
+pub(crate) const RESIZE_HANDLE_SIZE: u32 = 12;
+// https://gitlab.gnome.org/GNOME/gtk/-/blob/1bf88f1d81043fd99740e2f91e56ade7ede7303b/gtk/gtkwindow.c#L166
+pub(crate) const RESIZE_HANDLE_CORNER_SIZE: u32 = 24;
+pub(crate) const BORDER_SIZE: u32 = VISIBLE_BORDER_SIZE + RESIZE_HANDLE_SIZE;
 pub(crate) const HEADER_SIZE: u32 = 35;
 pub(crate) const CORNER_RADIUS: u32 = 10;
 pub(crate) const VISIBLE_BORDER_SIZE: u32 = 1;