stacking: Correctly restore decoration state

src/shell/element/mod.rs

@@ -505,6 +505,8 @@ impl CosmicMapped {
         outputs: impl Iterator<Item = (&'a Output, Rectangle<i32, Logical>)>,
     ) {
         let handle = self.loop_handle();
+        surface.try_force_undecorated(false);
+        surface.set_tiled(false);
         let window = CosmicWindow::new(surface, handle);
 
         if let Some(geo) = self.last_geometry.lock().unwrap().clone() {

src/shell/element/surface.rs

@@ -1,4 +1,4 @@
-use std::{cell::RefCell, time::Duration};
+use std::time::Duration;
 
 use smithay::{
     backend::renderer::{
@@ -38,7 +38,7 @@ use smithay::{
     xwayland::{xwm::X11Relatable, X11Surface},
 };
 
-use crate::state::SurfaceDmabufFeedback;
+use crate::{state::SurfaceDmabufFeedback, wayland::handlers::decoration::PreferredDecorationMode};
 
 space_elements! {
     #[derive(Debug, Clone, PartialEq)]
@@ -195,22 +195,14 @@ impl CosmicSurface {
                 if enable {
                     let previous_decoration_state =
                         window.toplevel().current_state().decoration_mode.clone();
-                    window
-                        .user_data()
-                        .insert_if_missing(|| RefCell::new(Option::<DecorationMode>::None));
-                    *window
-                        .user_data()
-                        .get::<RefCell<Option<DecorationMode>>>()
-                        .unwrap()
-                        .borrow_mut() = previous_decoration_state;
+                    if PreferredDecorationMode::is_unset(window) {
+                        PreferredDecorationMode::update(window, previous_decoration_state);
+                    }
                     window.toplevel().with_pending_state(|pending| {
                         pending.decoration_mode = Some(DecorationMode::ServerSide);
                     });
                 } else {
-                    let previous_mode = window
-                        .user_data()
-                        .get::<RefCell<Option<DecorationMode>>>()
-                        .and_then(|m| m.borrow().clone());
+                    let previous_mode = PreferredDecorationMode::mode(window);
                     window.toplevel().with_pending_state(|pending| {
                         pending.decoration_mode = previous_mode;
                     });

src/shell/layout/tiling/mod.rs

@@ -1217,6 +1217,8 @@ impl TilingLayout {
 
                         // map the rest
                         for other in surfaces {
+                            other.try_force_undecorated(false);
+                            other.set_tiled(false);
                             let window =
                                 CosmicMapped::from(CosmicWindow::new(other, handle.clone()));
                             window.output_enter(&output, window.bbox());

src/wayland/handlers/decoration.rs

@@ -1,5 +1,8 @@
+use std::cell::RefCell;
+
 use smithay::{
     delegate_kde_decoration, delegate_xdg_decoration,
+    desktop::Window,
     reexports::{
         wayland_protocols::xdg::decoration::zv1::server::zxdg_toplevel_decoration_v1::Mode as XdgMode,
         wayland_protocols_misc::server_decoration::server::org_kde_kwin_server_decoration::{
@@ -22,6 +25,38 @@ use crate::{
     state::State,
 };
 
+pub struct PreferredDecorationMode(RefCell<Option<XdgMode>>);
+
+impl PreferredDecorationMode {
+    pub fn is_unset(window: &Window) -> bool {
+        window
+            .user_data()
+            .get::<PreferredDecorationMode>()
+            .is_none()
+    }
+
+    pub fn mode(window: &Window) -> Option<XdgMode> {
+        let user_data = window.user_data();
+        user_data.insert_if_missing(|| PreferredDecorationMode(RefCell::new(None)));
+        user_data
+            .get::<PreferredDecorationMode>()
+            .unwrap()
+            .0
+            .borrow()
+            .clone()
+    }
+
+    pub fn update(window: &Window, update: Option<XdgMode>) {
+        let user_data = window.user_data();
+        user_data.insert_if_missing(|| PreferredDecorationMode(RefCell::new(None)));
+        *user_data
+            .get::<PreferredDecorationMode>()
+            .unwrap()
+            .0
+            .borrow_mut() = update;
+    }
+}
+
 impl State {
     pub fn new_decoration(mapped: &CosmicMapped, surface: &WlSurface) -> KdeMode {
         if mapped.is_stack() {
@@ -54,6 +89,7 @@ impl State {
             .windows()
             .find(|(window, _)| window.wl_surface().as_ref() == Some(surface))
         {
+            PreferredDecorationMode::update(&window, Some(mode));
             window.toplevel().with_pending_state(|state| {
                 state.decoration_mode = Some(mode);
             });
@@ -66,6 +102,7 @@ impl State {
             .windows()
             .find(|(window, _)| window.wl_surface().as_ref() == Some(surface))
         {
+            PreferredDecorationMode::update(&window, None);
             window.toplevel().with_pending_state(|state| {
                 state.decoration_mode = None;
             });