diff --git a/src/app.rs b/src/app.rs
index ea99b48..549adb3 100644
--- a/src/app.rs
+++ b/src/app.rs
@@ -816,6 +816,22 @@ pub trait App: 'static
 	/// **Default**: `None` (let the compositor pick).
 	fn window_size_hint( &self ) -> Option<( u32, u32 )> { None }
 
+	/// Whether the user may resize an xdg-shell window.
+	///
+	/// When [`Self::window_size_hint`] is set, ltk pins
+	/// `min_size == max_size` before the first commit so the compositor's
+	/// first configure honours the requested size, and then releases
+	/// `max_size` from the first configure so the surface becomes
+	/// user-resizable. Returning `false` skips that release: the pin stays
+	/// in place for the lifetime of the toplevel, declaring a fixed-size
+	/// window that compositors must not resize or restore a remembered
+	/// geometry over.
+	///
+	/// Ignored when [`Self::window_size_hint`] returns `None`.
+	///
+	/// **Default**: `true`.
+	fn window_resizable( &self ) -> bool { true }
+
 	/// Request fullscreen on the toplevel before its first commit.
 	///
 	/// When `true`, ltk calls `xdg_toplevel.set_fullscreen( None )` so
diff --git a/src/event_loop/run.rs b/src/event_loop/run.rs
index abe7d29..40bb30c 100644
--- a/src/event_loop/run.rs
+++ b/src/event_loop/run.rs
@@ -257,7 +257,7 @@ pub( crate ) fn try_run<A: App>( app: A ) -> Result<(), RunError>
 	let titlebar_title  = force_window.map( |( t, _ )| t ).unwrap_or_default();
 
 	let pending_fullscreen      = app.start_fullscreen();
-	let pending_size_hint_unpin = !app.start_fullscreen() && app.window_size_hint().is_some();
+	let pending_size_hint_unpin = !app.start_fullscreen() && app.window_size_hint().is_some() && app.window_resizable();
 
 	let mut data = AppData
 	{