feat(app-list): middle click app button to launch new window

cosmic-app-list/src/app.rs

@@ -257,18 +257,7 @@ impl DockItem {
                 mouse_area(
                     icon_button
                         .on_press_maybe(if toplevels.is_empty() {
-                            let gpu_idx = gpus.map(|gpus| {
+                            launch_on_preferred_gpu(desktop_info, gpus)
-                                if desktop_info.prefers_dgpu {
-                                    gpus.iter().position(|gpu| !gpu.default).unwrap_or(0)
-                                } else {
-                                    gpus.iter().position(|gpu| gpu.default).unwrap_or(0)
-                                }
-                            });
-
-                            desktop_info
-                                .exec
-                                .clone()
-                                .map(|exec| Message::Exec(exec, gpu_idx))
                         } else if toplevels.len() == 1 {
                             toplevels.first().map(|t| Message::Toggle(t.0.clone()))
                         } else {
@@ -277,7 +266,11 @@ impl DockItem {
                         .width(Length::Shrink)
                         .height(Length::Shrink),
                 )
-                .on_right_release(Message::Popup(desktop_info.id.clone())),
+                .on_right_release(Message::Popup(desktop_info.id.clone()))
+                .on_middle_release({
+                    launch_on_preferred_gpu(desktop_info, gpus)
+                        .unwrap_or_else(|| Message::Popup(desktop_info.id.clone()))
+                }),
             )
             .on_drag(|_| Message::StartDrag(desktop_info.id.clone()))
             .on_cancelled(Message::DragFinished)
@@ -1579,3 +1572,22 @@ impl CosmicAppList {
         None
     }
 }
+
+fn launch_on_preferred_gpu(
+    desktop_info: &DesktopEntryData,
+    gpus: Option<&[Gpu]>,
+) -> Option<Message> {
+    let Some(exec) = desktop_info.exec.clone() else {
+        return None;
+    };
+
+    let gpu_idx = gpus.map(|gpus| {
+        if desktop_info.prefers_dgpu {
+            gpus.iter().position(|gpu| !gpu.default).unwrap_or(0)
+        } else {
+            gpus.iter().position(|gpu| gpu.default).unwrap_or(0)
+        }
+    });
+
+    Some(Message::Exec(exec, gpu_idx))
+}