web/src/app.jsx

@@ -355,12 +355,24 @@ function App() {
       .catch(() => {});
   }, []);
 
-  // removeChannelTab closes a channel's tab and shows the Server tab.
+  // removeChannelTab closes a channel's tab. The tab the user was
+  // reading stays active, found by its name; when it was the closed tab,
+  // the Server tab shows.
   const removeChannelTab = useCallback((name) => {
-    setTabs((prev) =>
-      prev.filter((t) => !(t.type === "channel" && t.name === name)),
-    );
-    setActiveTab(0);
+    setTabs((prev) => {
+      const remaining = prev.filter(
+        (t) => !(t.type === "channel" && t.name === name),
+      );
+      // Preact runs this update at once, on the newest active tab.
+      setActiveTab((active) => {
+        const reading = prev[active]?.name;
+        const idx = remaining.findIndex((t) => t.name === reading);
+
+        return idx >= 0 ? idx : 0;
+      });
+
+      return remaining;
+    });
   }, []);
 
   const processMessage = useCallback(
@@ -453,6 +465,15 @@ function App() {
           const text = `${kicked} was kicked from ${msg.to} by ${msg.from}${reason}`;
           if (msg.to) addMessage(msg.to, { ...base, text, system: true });
           if (kicked === nickRef.current) {
+            // The channel's tab closes, so the Server tab gets the line
+            // too. It needs an id of its own: addMessage drops a message
+            // whose id it has already seen.
+            addMessage("Server", {
+              ...base,
+              id: msg.id + "-server",
+              text,
+              system: true,
+            });
             removeChannelTab(msg.to);
           } else if (msg.to && msg.to.startsWith("#")) {
             refreshMembers(msg.to);