fix: stack ordering command (#4308)

* fix: some issues with stacking panes

* cleanups and formatting

* docs(changelog): add PR

CHANGELOG.md

@@ -23,6 +23,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 * fix: out of bounds mouse release events (https://github.com/zellij-org/zellij/pull/4300)
 * fix: account for emoji/widechars when double/triple-clicking to mark words (https://github.com/zellij-org/zellij/pull/4302)
 * fix: allow pasting and emojis in tab/pane names and pasting in search (https://github.com/zellij-org/zellij/pull/4303)
+* fix: stack pane ordering when stacking multiple panes (https://github.com/zellij-org/zellij/pull/4308)
 
 ## [0.42.2] - 2025-04-15
 * refactor(terminal): track scroll_region as tuple rather than Option (https://github.com/zellij-org/zellij/pull/4082)

default-plugins/multiple-select/src/main.rs

@@ -186,20 +186,29 @@ impl App {
     fn update_grouped_panes(&mut self, pane_manifest: &PaneManifest, own_client_id: ClientId) {
         self.grouped_panes.clear();
         let mut count = 0;
+        let mut panes_with_index = Vec::new();
 
         for (_tab_index, pane_infos) in &pane_manifest.panes {
             for pane_info in pane_infos {
-                if pane_info.index_in_pane_group.get(&own_client_id).is_some() {
+                if let Some(index_in_pane_group) = pane_info.index_in_pane_group.get(&own_client_id)
+                {
                     let pane_id = if pane_info.is_plugin {
                         PaneId::Plugin(pane_info.id)
                     } else {
                         PaneId::Terminal(pane_info.id)
                     };
-                    self.grouped_panes.push(pane_id);
+                    panes_with_index.push((*index_in_pane_group, pane_id));
                     count += 1;
                 }
             }
         }
+
+        panes_with_index.sort_by_key(|(index, _)| *index);
+
+        for (_, pane_id) in panes_with_index {
+            self.grouped_panes.push(pane_id);
+        }
+
         if count == 0 {
             self.close_self();
         }

zellij-server/src/screen.rs

@@ -2768,13 +2768,14 @@ impl Screen {
         }
     }
     pub fn stack_panes(&mut self, mut pane_ids_to_stack: Vec<PaneId>) -> Option<PaneId> {
-        // if successful, returns the pane id of the root pane
+        // if successful, returns the pane id of the last pane in the stack
         if pane_ids_to_stack.is_empty() {
             log::error!("Got an empty list of pane_ids to stack");
             return None;
         }
         let stack_size = pane_ids_to_stack.len();
         let root_pane_id = pane_ids_to_stack.remove(0);
+        let last_pane_id = pane_ids_to_stack.last();
         let Some(root_tab_id) = self
             .tabs
             .iter()
@@ -2824,7 +2825,7 @@ impl Screen {
         self.tabs
             .get_mut(&root_tab_id)
             .map(|t| t.stack_panes(root_pane_id, panes_to_stack));
-        return Some(root_pane_id);
+        return last_pane_id.copied();
     }
     pub fn change_floating_panes_coordinates(
         &mut self,
@@ -5470,8 +5471,8 @@ pub(crate) fn screen_thread_main(
                 screen.set_floating_pane_pinned(pane_id, should_be_pinned);
             },
             ScreenInstruction::StackPanes(pane_ids_to_stack, client_id) => {
-                if let Some(root_pane_id) = screen.stack_panes(pane_ids_to_stack) {
+                if let Some(last_pane_id) = screen.stack_panes(pane_ids_to_stack) {
-                    let _ = screen.focus_pane_with_id(root_pane_id, false, client_id);
+                    let _ = screen.focus_pane_with_id(last_pane_id, false, client_id);
                     let _ = screen.unblock_input();
                     let _ = screen.render(None);
                     let pane_group = screen.get_client_pane_group(&client_id);

zellij-server/src/tab/mod.rs

@@ -5278,24 +5278,9 @@ impl Tab {
         }
         self.swap_layouts.set_is_tiled_damaged(); // TODO: verify we can do all the below first
         if self.pane_is_stacked(root_pane_id) {
-            if let Some(lowest_pane_id_in_stack) = self
-                .tiled_panes
-                .pane_ids_in_stack_of_pane_id(&root_pane_id)
-                .last()
-            {
-                // we get lowest_pane_id_in_stack so that we can extract the pane below and re-add
-                // it to its own stack - this has the effect of making it the last pane in the
-                // stack so that the rest of the panes will later be added below it - which makes
-                // sense from the perspective of the user
-                if let Some(pane) = self.extract_pane(root_pane_id, true) {
-                    self.tiled_panes
-                        .add_pane_to_stack(&lowest_pane_id_in_stack, pane);
-                }
-            }
             for pane in panes_to_stack.drain(..) {
                 self.tiled_panes.add_pane_to_stack(&root_pane_id, pane);
             }
-            self.tiled_panes.expand_pane_in_stack(root_pane_id);
         } else {
             // + 1 for the root pane
             let mut stack_geoms = self

zellij-server/src/unit/snapshots/zellij_server__screen__screen_tests__send_cli_stack_panes_action-2.snap

@@ -3,12 +3,12 @@ source: zellij-server/src/./unit/screen_tests.rs
 expression: "format!(\"{}\", snapshot)"
 ---
 00 (C): ┌ Pane #1 ─────┐┌ Pane #2 ─────────────────────────────────────┐┌ Pane #5 ─────┐
-01 (C): │              ││                                              ││              │
+01 (C): │              │┌ Pane #3 ─────────────────────────────────────┐│              │
-02 (C): │              ││                                              ││              │
+02 (C): │              │┌ Pane #4 ─────────────────────────────────────┐│              │
 03 (C): │              ││                                              ││              │
 04 (C): │              ││                                              ││              │
 05 (C): │              ││                                              ││              │
 06 (C): │              ││                                              ││              │
-07 (C): │              │└──────────────────────────────────────────────┘│              │
+07 (C): │              ││                                              ││              │
-08 (C): │              │└ Pane #3 ─────────────────────────────────────┘│              │
+08 (C): │              ││                                              ││              │
-09 (C): └──────────────┘└ Pane #4 ─────────────────────────────────────┘└──────────────┘
+09 (C): └──────────────┘└──────────────────────────────────────────────┘└──────────────┘