diff --git a/src/configuration.rs b/src/configuration.rs
new file mode 100644
index 0000000..57d4b06
--- /dev/null
+++ b/src/configuration.rs
@@ -0,0 +1,76 @@
+// Dergchat, a free XMPP client.
+// Copyright (C) 2023 Werner Kroneman
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+use dioxus::prelude::*;
+use keyring::Entry;
+use log::error;
+use serde_derive::{Deserialize, Serialize};
+use crate::widgets::login_screen::LoginAttempt;
+
+/// The configuration struct containing all the configuration options.
+#[derive(Serialize, Deserialize, Default)]
+pub struct Configuration {
+    pub stored_username: String,
+    pub stored_default_nick: String,
+}
+
+/// Cache the login attempt into the config and keyring.
+///
+/// Specifically, we store the username and default nick in the config file, and the password in the keyring.
+///
+/// Note: we do NOT store the password in the config file, because the latter is stored in plaintext.
+///
+/// # Arguments
+/// * `attempt` - The login attempt to store.
+/// * `config` - The current app configuration; UseState should prevent race conditions in writing.
+pub fn store_login_details(attempt: LoginAttempt, config: &mut UseRef<Configuration>) {
+
+    // Extract the fields from the login attempt.
+    let LoginAttempt {
+        username,
+        default_nick,
+        password,
+    } = attempt;
+
+    // Open the config state and store the username and default nick.
+    config.with_mut(|c| {
+
+        // Open the keyring and store the password.
+        let entry = Entry::new("dergchat", &username).expect("Failed to create keyring entry.");
+        entry.set_password(&password).expect("Failed to set password in keyring.");
+
+        // Store the username and default nick in the config.
+        c.stored_username = username;
+        c.stored_default_nick = default_nick;
+
+        if let Err(e) = confy::store("dergchat", None, c) {
+            error!("Failed to store the config file: {}", e);
+        }
+    });
+}
+
+/// Load the configuration from the config file.
+///
+/// On failure, log the error and return the default configuration.
+pub fn load_config() -> Configuration {
+    match confy::load("dergchat", None) {
+        Ok(x) => x,
+        Err(e) => {
+            error!("Failed to load config file: {}", e);
+            Configuration::default()
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/main.rs b/src/main.rs
index 22ffa73..2717174 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -19,6 +19,7 @@
 mod types;
 mod widgets;
 mod xmpp_interface;
+mod configuration;
 
 use dioxus::prelude::*;
 use dioxus_desktop::Config;
diff --git a/src/widgets/mod.rs b/src/widgets/mod.rs
index a61edeb..777e1f0 100644
--- a/src/widgets/mod.rs
+++ b/src/widgets/mod.rs
@@ -18,6 +18,7 @@ use crate::types::LoginCredentials;
 use crate::widgets::login_screen::LoginAttempt;
 use crate::widgets::login_screen::{LoginScreen, LoginStatus};
 use crate::widgets::room_view::RoomView;
+use crate::widgets::no_room_open::NoRoomPlaceholder;
 use crate::widgets::sidebar::SideBar;
 use crate::xmpp_interface::NetworkCommand;
 use dioxus::core::{Element, Scope};
@@ -31,7 +32,7 @@ use std::collections::HashMap;
 use std::str::FromStr;
 use std::string::String;
 use keyring::Entry;
-use serde_derive::{Deserialize, Serialize};
+use crate::configuration::load_config;
 use crate::xmpp_interface;
 
 pub mod login_screen;
@@ -40,14 +41,10 @@ pub mod room_list;
 pub mod room_view;
 pub mod send_message;
 pub mod sidebar;
-
-#[derive(Serialize, Deserialize, Default)]
-struct Configuration {
-    stored_username: String,
-    stored_default_nick: String,
-}
+mod no_room_open;
 
 pub fn App(cx: Scope) -> Element {
+
     let messages = use_ref(cx, || HashMap::new());
     let current_room = use_state(cx, || None::<BareJid>);
     let connection_status = use_state(cx, || LoginStatus::LoggedOut);
@@ -56,13 +53,7 @@ pub fn App(cx: Scope) -> Element {
         xmpp_interface::run_xmpp_toplevel(connection_status.to_owned(), messages.to_owned(), rx)
     });
 
-    let config = use_ref(cx, || match confy::load("dergchat", None) {
-        Ok(x) => x,
-        Err(e) => {
-            error!("Failed to load config file: {}", e);
-            Configuration::default()
-        }
-    });
+    let config = use_ref(cx, load_config);
 
     {
         let config = config.to_owned();
@@ -157,6 +148,9 @@ pub fn App(cx: Scope) -> Element {
                         current_room.set(None);
                         coroutine.send(NetworkCommand::LeaveRoom { room: x });
                     },
+                    on_join_room: move |x: BareJid| {
+                        coroutine.send(NetworkCommand::JoinRoom { room: x });
+                    },
                 }
 
                 // The current room.
@@ -173,21 +167,11 @@ pub fn App(cx: Scope) -> Element {
                     }
                 } else {
                     // No room selected
-                    NoRoomPlaceholder {}
+                    rsx! {
+                        NoRoomPlaceholder {}
+                    }
                 }
             }
         }
     }
-}
-
-fn NoRoomPlaceholder(cx: Scope) -> Element {
-    render! {
-        div {
-            padding: "5mm",
-            flex_grow: 1,
-            display: "flex",
-            background_color: "#166322",
-            "No room selected. Pick one from the list on the left."
-        }
-    }
-}
+}
\ No newline at end of file
diff --git a/src/widgets/no_room_open.rs b/src/widgets/no_room_open.rs
new file mode 100644
index 0000000..7c5ee54
--- /dev/null
+++ b/src/widgets/no_room_open.rs
@@ -0,0 +1,31 @@
+// Dergchat, a free XMPP client.
+// Copyright (C) 2023 Werner Kroneman
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+use dioxus::core::{Element, Scope};
+use dioxus::prelude::*;
+
+/// A placeholder widget for when no room is open.
+pub fn NoRoomPlaceholder(cx: Scope) -> Element {
+    render! {
+        div {
+            padding: "5mm",
+            flex_grow: 1,
+            display: "flex",
+            background_color: "#166322",
+            "No room selected. Pick one from the list on the left."
+        }
+    }
+}
diff --git a/src/widgets/room_join_widget.rs b/src/widgets/room_join_widget.rs
index 230d072..b860eac 100644
--- a/src/widgets/room_join_widget.rs
+++ b/src/widgets/room_join_widget.rs
@@ -18,18 +18,25 @@ use dioxus::core::{Element, Scope};
 use dioxus::core_macro::Props;
 use dioxus::hooks::use_state;
 use dioxus::prelude::*;
+use jid::BareJid;
+use std::str::FromStr;
 
 /// The props for the room join widget, including:
 /// * The event handler for when the user clicks the join button, passing in a room name. This name is not validated in any way.
 #[derive(Props)]
 pub struct RoomJoinProps<'a> {
-    on_join_room: EventHandler<'a, String>,
+    on_join_room: EventHandler<'a, BareJid>,
 }
 
 /// A simple widget that allows the user to join a room by typing
 /// its name into a text field and clicking a button.
+///
+/// Also validates the room name, and displays an error message if the room name is invalid.
 pub fn RoomJoinWidget<'a>(cx: Scope<'a, RoomJoinProps>) -> Element<'a> {
+
+    // Store the current room name and error message in state.
     let room = use_state(cx, || "".to_owned());
+    let error = use_state(cx, || "".to_owned());
 
     render! {
         div {
@@ -39,11 +46,19 @@ pub fn RoomJoinWidget<'a>(cx: Scope<'a, RoomJoinProps>) -> Element<'a> {
                 flex_grow: 1,
                 display: "block",
                 oninput: |evt| {
-                    room.set(evt.value.clone());
+                    room.set(evt.value.to_string());
+                    error.set("".to_owned());
                 }
             }
             button {
-                onclick: move |_| cx.props.on_join_room.call(room.current().to_string()),
+                onclick: move |_| {
+                    // Validate the room name. If it's a valid Jid, try to join it.
+                    // Otherwise, display an error message.
+                    match BareJid::from_str(room.current().as_str()) {
+                        Ok(jid) => {error.set("".to_string()); cx.props.on_join_room.call(jid);},
+                        Err(e) => {error.set(e.to_string());},
+                    }
+                },
                 "Join"
             }
         }
diff --git a/src/widgets/sidebar.rs b/src/widgets/sidebar.rs
index d418122..8f4e397 100644
--- a/src/widgets/sidebar.rs
+++ b/src/widgets/sidebar.rs
@@ -22,14 +22,15 @@ use crate::widgets::room_list::RoomList;
 use crate::widgets::room_join_widget::RoomJoinWidget;
 
 #[derive(Props)]
-pub struct SideBarProps {
+pub struct SideBarProps<'a> {
     pub rooms: Vec<BareJid>,
-    pub on_room_picked: EventHandler<'static, BareJid>,
-    pub on_room_left: EventHandler<'static, BareJid>,
+    pub on_room_picked: EventHandler<'a, BareJid>,
+    pub on_room_left: EventHandler<'a, BareJid>,
+    pub on_join_room: EventHandler<'a, BareJid>,
 }
 
 /// A widget that combines the RoomList, RoomJoinWidget, and current user info into a sidebar.
-pub fn SideBar(cx: Scope<SideBarProps>) -> Element {
+pub fn SideBar<'a>(cx: Scope<'a, SideBarProps>) -> Element<'a> {
     render! {
         div {
             padding: "5mm",
@@ -46,15 +47,13 @@ pub fn SideBar(cx: Scope<SideBarProps>) -> Element {
             // The list of rooms.
             RoomList {
                 rooms: cx.props.rooms.clone(),
-                on_room_picked: cx.props.on_room_picked.clone(),
-                on_room_left: cx.props.on_room_left.clone(),
+                on_room_picked: |e| cx.props.on_room_picked.call(e),
+                on_room_left: |e| cx.props.on_room_left.call(e),
             }
 
             // The widget to join a room.
             RoomJoinWidget {
-                on_join_room: |x: String| {
-                    println!("Joining room: {:?}", x);
-                },
+                on_join_room: |x| cx.props.on_join_room.call(x),
             }
         }
     }