diff --git a/melib/src/async.rs b/melib/src/async.rs
index 42aa5dd7a..26a024a1a 100644
--- a/melib/src/async.rs
+++ b/melib/src/async.rs
@@ -1,13 +1,28 @@
+/*!
+ * Primitive Async/Wait implementation.
+ *
+ * To create an Async promise, create an AsyncBuilder. Ask for its channel receiver/sender with
+ * `tx` and `rx` methods to pass them in your worker's closure. Build an `Async<T>` with your
+ * `JoinHandle<T>`. The thread must communicate with the `Async<T>` object via `AsyncStatus`
+ * messages.
+ *
+ * When `Async<T>` receives `AsyncStatus::Finished` it joins the thread and takes its value which
+ * can be extracted with `extract`.
+ */
+
 use chan;
 use std::thread;
 
+/// Messages to pass between `Async<T>` owner and its worker thread.
 #[derive(Debug)]
 pub enum AsyncStatus {
     NoUpdate,
     Finished,
+    ///The number may hold whatever meaning the user chooses.
     ProgressReport(usize),
 }
 
+/// A builder object for `Async<T>`
 #[derive(Debug)]
 pub struct AsyncBuilder {
     tx: chan::Sender<AsyncStatus>,
@@ -22,8 +37,6 @@ pub struct Async<T> {
     rx: chan::Receiver<AsyncStatus>,
 }
 
-
-
 impl AsyncBuilder {
     pub fn new() -> Self {
         let (sender, receiver) = chan::sync(::std::mem::size_of::<AsyncStatus>());
@@ -32,12 +45,15 @@ impl AsyncBuilder {
             rx: receiver,
         }
     }
+    /// Returns the sender object of the promise's channel.
     pub fn tx(&mut self) -> chan::Sender<AsyncStatus> {
         self.tx.clone()
     }
+    /// Returns the receiver object of the promise's channel.
     pub fn rx(&mut self) -> chan::Receiver<AsyncStatus> {
         self.rx.clone()
     }
+    /// Returns an `Async<T>` object that contains a `Thread` join handle that returns a `T`
     pub fn build<T: Clone>(self, worker: thread::JoinHandle<T>) -> Async<T> {
         Async {
             worker: Some(worker),
@@ -49,9 +65,11 @@ impl AsyncBuilder {
 }
 
 impl<T> Async<T> {
+    /// Consumes `self` and returns the computed value. Will panic if computation hasn't finished.
     pub fn extract(self) -> T {
         self.value.unwrap()
     }
+    /// Polls worker thread and returns result. 
     pub fn poll(&mut self) -> Result<AsyncStatus, ()> {
         if self.value.is_some() {
             return Ok(AsyncStatus::Finished);
diff --git a/melib/src/error.rs b/melib/src/error.rs
index 2aaec9e12..c0c9b581f 100644
--- a/melib/src/error.rs
+++ b/melib/src/error.rs
@@ -18,6 +18,11 @@
  * You should have received a copy of the GNU General Public License
  * along with meli. If not, see <http://www.gnu.org/licenses/>.
  */
+
+/*!
+ * An error object for `melib`
+ */
+
 use std::error::Error;
 use std::fmt;
 use std::io;
diff --git a/melib/src/lib.rs b/melib/src/lib.rs
index d953ff456..56d7d740c 100644
--- a/melib/src/lib.rs
+++ b/melib/src/lib.rs
@@ -21,7 +21,6 @@
 pub mod conf;
 pub mod error;
 pub mod mailbox;
-pub mod utilities;
 pub mod async;
 
 #[macro_use]
@@ -45,4 +44,3 @@ pub use mailbox::*;
 pub use error::{MeliError, Result};
 pub use mailbox::backends::{Backends, RefreshEvent, RefreshEventConsumer};
 pub use mailbox::email::{Envelope, Flag};
-pub use utilities::*;
diff --git a/melib/src/mailbox/accounts.rs b/melib/src/mailbox/accounts.rs
index 5f11a8c76..82fb34287 100644
--- a/melib/src/mailbox/accounts.rs
+++ b/melib/src/mailbox/accounts.rs
@@ -19,6 +19,10 @@
  * along with meli. If not, see <http://www.gnu.org/licenses/>.
  */
 
+/*!
+ * Account management from user configuration.
+ */
+
 use conf::{AccountSettings, Folder};
 use mailbox::backends::{Backends, RefreshEventConsumer};
 use mailbox::*;
diff --git a/melib/src/mailbox/email/mod.rs b/melib/src/mailbox/email/mod.rs
index d300a6919..53aba9903 100644
--- a/melib/src/mailbox/email/mod.rs
+++ b/melib/src/mailbox/email/mod.rs
@@ -19,6 +19,9 @@
  * along with meli. If not, see <http://www.gnu.org/licenses/>.
  */
 
+/*!
+ * Email parsing, handling, sending etc.
+ */
 pub mod attachments;
 pub mod parser;
 
diff --git a/melib/src/mailbox/mod.rs b/melib/src/mailbox/mod.rs
index 720cbe516..d9d9eb84d 100644
--- a/melib/src/mailbox/mod.rs
+++ b/melib/src/mailbox/mod.rs
@@ -19,6 +19,12 @@
  * along with meli. If not, see <http://www.gnu.org/licenses/>.
  */
 
+/*!
+ * Mail related code.
+ *
+ * This module handles reading emails from various backends, handling account data etc
+ */
+
 pub mod email;
 pub use self::email::*;
 /* Mail backends. Currently only maildir is supported */
diff --git a/melib/src/mailbox/thread.rs b/melib/src/mailbox/thread.rs
index c94e17f98..8207de19d 100644
--- a/melib/src/mailbox/thread.rs
+++ b/melib/src/mailbox/thread.rs
@@ -19,6 +19,10 @@
  * along with meli. If not, see <http://www.gnu.org/licenses/>.
  */
 
+/*!
+ * Threading algorithm
+ */
+
 use error::Result;
 use mailbox::email::*;
 use mailbox::Mailbox;
@@ -262,6 +266,7 @@ pub fn build_threads(
 
             for x in &sent_mailbox.collection {
                 let m_id = x.message_id_raw();
+                let x_r_id = x.in_reply_to_raw();
                 if id_table.contains_key(&m_id)
                     || (!x.in_reply_to_raw().is_empty()
                         && id_table.contains_key(&x.in_reply_to_raw()))
@@ -280,7 +285,7 @@ pub fn build_threads(
                     } else if !x.in_reply_to_raw().is_empty()
                         && id_table.contains_key(&x.in_reply_to_raw())
                     {
-                        let p = id_table[&m_id];
+                        let p = id_table[&x_r_id];
                         let c = if id_table.contains_key(&m_id) {
                             id_table[&m_id]
                         } else {
diff --git a/melib/src/utilities.rs b/melib/src/utilities.rs
deleted file mode 100644
index 438014c9d..000000000
--- a/melib/src/utilities.rs
+++ /dev/null
@@ -1,11 +0,0 @@
-
-pub trait ProgressTracker {
-    fn new(s: String, total_work: usize) -> Self;
-
-    fn add_work(&mut self, n: usize) -> ();
-    fn set_work(&mut self, n: usize) -> ();
-    fn work(&mut self, n: usize) -> ();
-
-    fn percentage(&self) -> usize;
-    fn description(&self) -> &str;
-}
diff --git a/src/bin.rs b/src/bin.rs
index 97552895c..064acfb93 100644
--- a/src/bin.rs
+++ b/src/bin.rs
@@ -33,7 +33,7 @@ extern crate melib;
 extern crate ui;
 
 pub use melib::*;
-use ui::*;
+pub use ui::*;
 
 use std::thread;
 
@@ -206,10 +206,10 @@ fn main() {
                                     }
                                 }
                             }
-                           if !flag {
-                               state.finish_startup();
-                           }
-                               
+                            if !flag {
+                                state.finish_startup();
+                            }
+                            state.render();
                         }
                         ThreadEvent::UIEvent(e) => {
                             state.rcv_event(UIEvent { id: 0, event_type: e});
diff --git a/ui/src/components/mail/mod.rs b/ui/src/components/mail/mod.rs
index 04d785f6b..775c4f7bf 100644
--- a/ui/src/components/mail/mod.rs
+++ b/ui/src/components/mail/mod.rs
@@ -14,6 +14,7 @@ struct AccountMenuEntry {
     entries: Vec<(usize, Folder)>,
 }
 
+/// The account sidebar.
 #[derive(Debug)]
 pub struct AccountMenu {
     accounts: Vec<AccountMenuEntry>,
diff --git a/ui/src/execute/actions.rs b/ui/src/execute/actions.rs
index f4ccb55e7..bf556c4db 100644
--- a/ui/src/execute/actions.rs
+++ b/ui/src/execute/actions.rs
@@ -1,3 +1,7 @@
+/*!
+ * User actions that need to be handled by the UI
+ */
+
 #[derive(Debug)]
 pub enum MailListingAction {
     ToggleThreaded,
diff --git a/ui/src/lib.rs b/ui/src/lib.rs
index 7bd9497d6..9d49f4dbb 100644
--- a/ui/src/lib.rs
+++ b/ui/src/lib.rs
@@ -19,6 +19,10 @@
  * along with meli. If not, see <http://www.gnu.org/licenses/>.
  */
 
+/*!
+ * This library exports the public types and methods of its modules
+ */
+
 extern crate melib;
 extern crate mime_apps;
 extern crate notify_rust;
diff --git a/ui/src/state.rs b/ui/src/state.rs
index bcd9b5afd..2a335ede5 100644
--- a/ui/src/state.rs
+++ b/ui/src/state.rs
@@ -1,4 +1,5 @@
-/*!
+/*! The application's state.
+
   The UI crate has an Entity-Component-System design. The System part, is also the application's state, so they're both merged in the `State` struct.
 
   `State` owns all the Entities of the UI, which are currently plain Containers for `Component`s. In the application's main event loop, input is handed to the state in the form of `UIEvent` objects which traverse the entity graph. Components decide to handle each input or not.
@@ -158,11 +159,15 @@ impl State<std::io::Stdout> {
         s
     }
 
+    /// If an owned thread returns a `ThreadEvent::ThreadJoin` event to `State` then it must remove
+    /// the thread from its list and `join` it.
     pub fn join(&mut self, id: thread::ThreadId) {
         let handle = self.threads.remove(&id).unwrap();
         handle.join().unwrap();
     }
 
+    /// If startup has finished, inform startup thread that it doesn't need to tick us with startup
+    /// check reminders and let it die.
     pub fn finish_startup(&mut self) {
         // TODO: Encode startup process with the type system if possible
         if self.startup_thread.is_none() {
@@ -173,6 +178,9 @@ impl State<std::io::Stdout> {
             tx.send(true);
         }
     }
+
+    /// Switch back to the terminal's main screen (The command line the user sees before opening
+    /// the application)
     pub fn to_main_screen(&mut self) {
         write!(
             self.stdout(),
@@ -199,6 +207,7 @@ impl State<std::io::Stdout> {
     }
 }
 impl<W: Write> State<W> {
+    /// On `SIGWNICH` the `State` redraws itself according to the new terminal size.
     pub fn update_size(&mut self) {
         let termsize = termion::terminal_size().ok();
         let termcols = termsize.map(|(w, _)| w);
@@ -221,6 +230,7 @@ impl<W: Write> State<W> {
         });
     }
 
+    /// Force a redraw for all dirty components.
     pub fn redraw(&mut self) {
         for i in 0..self.entities.len() {
             self.draw_entity(i);
@@ -231,6 +241,8 @@ impl<W: Write> State<W> {
             self.draw_area(a);
         }
     }
+
+    /// Draw only a specific `area` on the screen.
     fn draw_area(&mut self, area: Area) {
         let upper_left = upper_left!(area);
         let bottom_right = bottom_right!(area);
@@ -269,6 +281,8 @@ impl<W: Write> State<W> {
         }
         self.flush();
     }
+
+    /// Draw the entire screen from scratch.
     pub fn render(&mut self) {
         self.update_size();
 
@@ -306,6 +320,7 @@ impl<W: Write> State<W> {
         }
     }
 
+    /// The application's main loop sends `UIEvents` to state via this method.
     pub fn rcv_event(&mut self, event: UIEvent) {
         match event.event_type {
             // Command type is handled only by State.
@@ -383,6 +398,8 @@ impl<W: Write> State<W> {
             });
         }
     }
+
+    
     pub fn try_wait_on_child(&mut self) -> Option<bool> {
         if {
             match self.child {