diff --git a/crates/ui-egui/src/live.rs b/crates/ui-egui/src/live.rs
index bcc0bc77..c4ea3ed7 100644
--- a/crates/ui-egui/src/live.rs
+++ b/crates/ui-egui/src/live.rs
@@ -98,10 +98,11 @@ pub struct LiveUi {
     pub advanced: bool,
     pub this_computer: bool,
     pub port: String,
-    /// The server key for online sharing (a server that needs one; empty: none). Passed to
-    /// `collab.share` so a keyed server can be used from the Share popover without the Publish
-    /// dialog.
-    pub share_key: String,
+    /// The server key for online sharing, and the server address it was entered for (a server
+    /// that needs one; `None`: none). Passed to `collab.share` so a keyed server can be used
+    /// from the Share popover without the Publish dialog. The key goes out only to the server it
+    /// belongs to: switching the server in Preferences must not leak the old one to it.
+    pub share_key: Option<(String, String)>,
     /// What is typed in the join field of the Share popover and the home screen.
     pub code: String,
     /// The join started from the home screen: what it is doing shows under the field, and its
@@ -750,8 +751,14 @@ fn start_ui(app: &mut FigApp, ui: &mut Ui, t: &Tokens) {
         if let (true, Ok(port)) = (local, app.ui.live.port.trim().parse::<u16>()) {
             params["port"] = json!(port);
         }
-        if !local && !app.ui.live.share_key.trim().is_empty() {
-            params["key"] = json!(app.ui.live.share_key.trim());
+        // The key goes out only to the server it belongs to (the server in Preferences): changing
+        // the server must not send the old server's key to a new one.
+        if !local
+            && let Some((at, key)) = app.ui.live.share_key.as_ref()
+            && *at == server
+            && !key.is_empty()
+        {
+            params["key"] = json!(key);
         }
         app.run("collab.share", params);
     }
@@ -770,12 +777,13 @@ fn start_ui(app: &mut FigApp, ui: &mut Ui, t: &Tokens) {
         } else {
             widgets::label(ui, tr("Another server, or one that needs its key. The usual server is set in Preferences."), t.text_secondary);
             // The server key (a server that needs one; the address in Preferences is without it).
+            // It is remembered for the server it was typed for, so it never leaks to another one.
             ui.horizontal(|ui| {
                 widgets::label(ui, tr("Server key"), t.text);
-                if let Some(key) =
-                    widgets::secret_field_named(ui, egui::Id::unique("live_share_key"), &app.ui.live.share_key, 200.0, tr("Server key"))
-                {
-                    app.ui.live.share_key = key.trim().chars().filter(|c| !c.is_whitespace() && !c.is_control()).take(128).collect();
+                let shown = app.ui.live.share_key.as_ref().map(|(_, key)| key.as_str()).unwrap_or_default();
+                if let Some(key) = widgets::secret_field_named(ui, egui::Id::unique("live_share_key"), shown, 200.0, tr("Server key")) {
+                    let key: String = key.trim().chars().filter(|c| !c.is_whitespace() && !c.is_control()).take(128).collect();
+                    app.ui.live.share_key = if key.is_empty() { None } else { Some((server.trim().to_string(), key)) };
                 }
             });
             if widgets::button(ui, tr("Publish to another server…"), false, true).clicked() {
diff --git a/crates/ui-egui/src/live_share_tests.rs b/crates/ui-egui/src/live_share_tests.rs
index 6c5bdb84..edef3acc 100644
--- a/crates/ui-egui/src/live_share_tests.rs
+++ b/crates/ui-egui/src/live_share_tests.rs
@@ -237,7 +237,7 @@ fn the_server_key_shows_as_dots_while_shown_and_typed() {
     let (mut h, _) = harness();
     let shapes = open(&mut h);
     click(&mut h, &shapes, "Advanced");
-    h.app.ui.live.share_key = "s3cret-key".into();
+    h.app.ui.live.share_key = Some(("wss://share.example/".to_string(), "s3cret-key".to_string()));
     let shapes = h.frames(2);
     let dots = "•".repeat(10);
     assert!(has_text(&shapes, &dots) && !has_text(&shapes, "s3cret-key"));
@@ -505,6 +505,22 @@ fn the_server_preference_resets_and_turns_online_sharing_off() {
     assert!(s.published.is_empty() && s.hosted.len() == 1, "shared on the local network");
 }
 
+#[test]
+fn a_key_typed_for_one_server_is_not_sent_to_another() {
+    // The Server key field remembers the server it was typed for: it goes out only to that
+    // server. Changing the server in Preferences must not send the old server's key to the new
+    // one. (The key is set as the field editor would, bound to the server it was typed for.)
+    let (mut h, script) = harness();
+    h.app.ui.live.share_key = Some(("wss://share.example/".to_string(), "KeyKeyKeyKeyKeyKeyKey0".to_string()));
+    h.frames(2);
+    // Change the server in Preferences to another one, then share: the old key must not go to it.
+    h.app.session.execute("pref.publishServer", &json!({"url": "wss://other.example/"})).unwrap();
+    h.frames(2);
+    let shapes = open(&mut h);
+    let shapes = click(&mut h, &shapes, "Start sharing");
+    assert_eq!(script.lock().unwrap().published.last().unwrap().key, None, "the old server's key is not sent to the new server");
+}
+
 #[test]
 fn an_open_popover_asks_for_no_frames() {
     let (mut h, script) = harness();