#1151: Preferences › Performance › Linux display server opens the window through Xwayland, where file drops work

winit 0.30 delivers no file drops on native Wayland. The new Linux Display
Server preference (Automatic / X11 (XWayland), shown on Linux only, read at
startup) has winit open the window on X11 when the session is Wayland,
DISPLAY is set and the X11 libraries winit loads are installed (ldconfig
check ported from PhotoCraft); otherwise the window opens on Wayland and
the log says why. README, development notes, parity docs, ROADMAP and the
complete catalogs updated.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

crates/engine/src/cmd/prefscmds.rs

@@ -87,6 +87,10 @@ const LINE_STYLE: &[(&str, &str)] = &[("lines", "Lines"), ("dots", "Dots")];
 /// `automatic` (#502).
 pub const GPU_PREFERENCES: &[(&str, &str)] =
     &[("automatic", "Automatic"), ("lowPower", "Power Saving (integrated)"), ("highPerformance", "High Performance (discrete)")];
+/// Performance › Linux Display Server (`linuxDisplayServer`), read by the desktop app at startup:
+/// `x11` opens the window through XWayland on a Wayland session, where dropped files arrive
+/// (winit 0.30 has no Wayland drag and drop, #1151).
+const LINUX_DISPLAY_SERVERS: &[(&str, &str)] = &[("automatic", "Automatic"), ("x11", "X11 (XWayland)")];
 const BLACK: &[(&str, &str)] = &[("accurate", "Display All Blacks Accurately"), ("rich", "Display All Blacks as Rich Black")];
 const BLACK_OUT: &[(&str, &str)] = &[("accurate", "Output All Blacks Accurately"), ("rich", "Output All Blacks as Rich Black")];
 
@@ -290,6 +294,7 @@ pub const PREF_SPECS: &[PrefSpec] = &[
     p!("historyStates", "Performance", "", "History States", int(5, 1000)),
     p!("realTimeDrawing", "Performance", "", "Real-time Drawing and Editing", bool),
     p!("renderThreads", "Performance", "", "Render Threads (-1 = Automatic)", int(-1, 64)),
+    p!("linuxDisplayServer", "Performance", "", "Linux Display Server", choice(LINUX_DISPLAY_SERVERS)),
     // File Handling
     p!("backgroundSave", "File Handling", "", "Enable Background Save", bool),
     p!("backgroundExport", "File Handling", "", "Enable Background Export", bool),

crates/engine/src/lib.rs

@@ -564,6 +564,9 @@ pub struct Prefs {
     pub real_time_drawing: bool,
     /// Rasterizer worker threads; -1 = automatic.
     pub render_threads: i32,
+    /// Linux: `automatic` opens the window on the session's display server; `x11` opens it through
+    /// XWayland on a Wayland session, where dropped files arrive (#1151). Read when the app starts.
+    pub linux_display_server: String,
     // File Handling
     pub background_save: bool,
     pub background_export: bool,
@@ -769,6 +772,7 @@ impl Default for Prefs {
             history_states: 500,
             real_time_drawing: true,
             render_threads: -1,
+            linux_display_server: s("automatic"),
             background_save: true,
             background_export: true,
             autosave_recovery: true,

crates/engine/src/tests_prefs.rs

@@ -156,6 +156,23 @@ fn gpu_preference_defaults_to_automatic_and_validates() {
     assert_eq!(s.prefs.gpu_preference, "automatic");
 }
 
+/// Performance › Linux Display Server (#1151): automatic by default, X11 by value or label, and
+/// anything else is an error that changes nothing.
+#[test]
+fn linux_display_server_defaults_to_automatic_and_validates() {
+    let mut s = Session::new();
+    assert_eq!(s.prefs.linux_display_server, "automatic");
+    s.execute("prefs.set", &json!({"key": "linuxDisplayServer", "value": "X11 (XWayland)"})).unwrap();
+    assert_eq!(s.prefs.linux_display_server, "x11");
+    for bad in [json!("wayland"), json!(""), json!(11), json!(null)] {
+        assert!(s.execute("prefs.set", &json!({"key": "linuxDisplayServer", "value": bad})).is_err(), "{bad}");
+        assert_eq!(s.prefs.linux_display_server, "x11");
+    }
+    assert_eq!(s.prefs.to_json()["linuxDisplayServer"], "x11");
+    s.execute("prefs.reset", &json!({"category": "Performance"})).unwrap();
+    assert_eq!(s.prefs.linux_display_server, "automatic");
+}
+
 /// Selection & Anchor Display › Tolerance, Object Selection by Path Only and Command Click to
 /// Select Objects Behind, and General › Double Click To Isolate, as the Selection tool sees them
 /// (#394).