diff --git a/README.md b/README.md
index 6f7f1207..9e4b2ea5 100644
--- a/README.md
+++ b/README.md
@@ -24,10 +24,8 @@ No idea which one are relevant at the moment
 
 # Tests
 
-sudo is required because some tests actually read /dev stuff.
-
 ```bash
-sudo python3 setup.py install && sudo python3 tests/test.py
+sudo python3 setup.py install && python3 tests/test.py
 ```
 
 # Roadmap
diff --git a/bin/key-mapper-gtk b/bin/key-mapper-gtk
index 810dfa88..700ca0a7 100755
--- a/bin/key-mapper-gtk
+++ b/bin/key-mapper-gtk
@@ -32,7 +32,7 @@ from gi.repository import Gtk, Gdk, GLib
 
 from keymapper.data import get_data_path
 from keymapper.X import create_setxkbmap_config, apply_preset, \
-    create_preset, Mapping
+    create_preset, mapping
 from keymapper.presets import get_presets, find_newest_preset, \
     delete_preset, rename_preset
 from keymapper.logger import logger, update_verbosity, log_info
@@ -43,7 +43,6 @@ window = None
 
 
 # TODO check for sudo rights
-# TODO NUM1 doesnt work anymore
 
 
 def gtk_iteration():
@@ -54,7 +53,10 @@ def gtk_iteration():
 
 keycode_reader = KeycodeReader()
 
-mapping = Mapping()
+
+CTX_SAVE = 0
+CTX_APPLY = 1
+CTX_KEYCODE = 2
 
 
 class SingleKeyMapping:
@@ -109,10 +111,13 @@ class SingleKeyMapping:
 
         # keycode is already set by some other row
         if mapping.get(new_keycode) is not None:
-            logger.info('Keycode %s is already mapped', new_keycode)
+            msg = f'Keycode {new_keycode} is already mapped'
+            logger.info(msg)
+            window.get('status_bar').push(CTX_KEYCODE, msg)
             return
 
         # it's legal to display the keycode
+        window.get('status_bar').remove_all(CTX_KEYCODE)
         self.keycode.set_label(str(new_keycode))
 
         # the character is empty and therefore the mapping is not complete
@@ -185,7 +190,9 @@ class SingleKeyMapping:
 
     def on_delete_button_clicked(self, *args):
         """Destroy the row and remove it from the config."""
-        mapping.clear()
+        keycode = self.get_keycode()
+        if keycode is not None:
+            mapping.clear(keycode)
         self.delete_callback(self)
 
 
@@ -195,6 +202,14 @@ class Window:
         self.selected_device = None
         self.selected_preset = None
 
+        css_provider = Gtk.CssProvider()
+        css_provider.load_from_path(get_data_path('style.css'))
+        Gtk.StyleContext.add_provider_for_screen(
+            Gdk.Screen.get_default(),
+            css_provider,
+            Gtk.STYLE_PROVIDER_PRIORITY_APPLICATION
+        )
+
         gladefile = get_data_path('key-mapper.glade')
         builder = Gtk.Builder()
         builder.add_from_file(gladefile)
@@ -209,13 +224,7 @@ class Window:
 
         self.select_newest_preset()
 
-        css_provider = Gtk.CssProvider()
-        css_provider.load_from_path(get_data_path('style.css'))
-        Gtk.StyleContext.add_provider_for_screen(
-            Gdk.Screen.get_default(),
-            css_provider,
-            Gtk.STYLE_PROVIDER_PRIORITY_APPLICATION
-        )
+        GLib.timeout_add(100, self.check_add_row)
 
     def get(self, name):
         """Get a widget from the window"""
@@ -225,6 +234,18 @@ class Window:
         """Safely close the application."""
         Gtk.main_quit()
 
+    def check_add_row(self):
+        """Ensure that one empty row is available at all times."""
+        rows = len(self.get('key_list').get_children())
+
+        # verify that all mappings are displayed
+        assert rows >= len(mapping)
+
+        if rows == len(mapping):
+            self.add_empty()
+
+        return True
+
     def select_newest_preset(self):
         """Find and select the newest preset."""
         device, preset = find_newest_preset()
@@ -269,10 +290,16 @@ class Window:
     def on_save_preset_clicked(self, button):
         """Save changes to a preset to the file system."""
         new_name = self.get('preset_name_input').get_text()
+        self.save_config()
         if new_name != '' and new_name != self.selected_preset:
             rename_preset(self.selected_device, self.selected_preset, new_name)
-            self.populate_presets()
-        self.save_config()
+        # after saving the config, its modification date will be the newest,
+        # so populate_presets will automatically select the right one again.
+        self.populate_presets()
+        self.get('status_bar').push(
+            CTX_SAVE,
+            f'Saved "{self.selected_preset}"'
+        )
 
     def on_delete_preset_clicked(self, button):
         """Delete a preset from the file system."""
@@ -287,6 +314,10 @@ class Window:
             self.selected_device
         )
         apply_preset(self.selected_device, self.selected_preset)
+        self.get('status_bar').push(
+            CTX_APPLY,
+            f'Applied "{self.selected_preset}"'
+        )
 
     def on_select_device(self, dropdown):
         """List all presets, create one if none exist yet."""
@@ -369,6 +400,9 @@ class Window:
             self.selected_preset
         )
 
+        print('lkjahsdfkjashdkj')
+        print(list(mapping))
+
         create_setxkbmap_config(
             self.selected_device,
             self.selected_preset,
diff --git a/data/key-mapper.glade b/data/key-mapper.glade
index dda82022..c44c9b87 100644
--- a/data/key-mapper.glade
+++ b/data/key-mapper.glade
@@ -87,6 +87,7 @@
                         <property name="visible">True</property>
                         <property name="can_focus">True</property>
                         <property name="receives_default">True</property>
+                        <property name="tooltip_text" translatable="yes">In order to apply any changes, save the preset first.</property>
                         <property name="use_stock">True</property>
                         <signal name="clicked" handler="on_apply_preset_clicked" swapped="no"/>
                       </object>
@@ -230,11 +231,41 @@
                 </child>
               </object>
               <packing>
-                <property name="expand">False</property>
+                <property name="expand">True</property>
                 <property name="fill">True</property>
                 <property name="position">2</property>
               </packing>
             </child>
+            <child>
+              <object class="GtkSeparator">
+                <property name="visible">True</property>
+                <property name="can_focus">False</property>
+              </object>
+              <packing>
+                <property name="expand">False</property>
+                <property name="fill">True</property>
+                <property name="position">3</property>
+              </packing>
+            </child>
+            <child>
+              <object class="GtkStatusbar" id="status_bar">
+                <property name="visible">True</property>
+                <property name="can_focus">False</property>
+                <property name="margin_left">10</property>
+                <property name="margin_right">10</property>
+                <property name="margin_start">10</property>
+                <property name="margin_end">10</property>
+                <property name="margin_top">6</property>
+                <property name="margin_bottom">6</property>
+                <property name="orientation">vertical</property>
+                <property name="spacing">2</property>
+              </object>
+              <packing>
+                <property name="expand">False</property>
+                <property name="fill">True</property>
+                <property name="position">4</property>
+              </packing>
+            </child>
           </object>
           <packing>
             <property name="expand">False</property>
@@ -267,6 +298,7 @@
                   <object class="GtkLabel">
                     <property name="visible">True</property>
                     <property name="can_focus">False</property>
+                    <property name="tooltip_text" translatable="yes">Click on a cell below and hit a key on your device</property>
                     <property name="margin_top">5</property>
                     <property name="margin_bottom">5</property>
                     <property name="label" translatable="yes">Key</property>
@@ -282,6 +314,11 @@
                   <object class="GtkLabel">
                     <property name="visible">True</property>
                     <property name="can_focus">False</property>
+                    <property name="tooltip_text" translatable="yes">a-z, A-Z, 0-9
+KP_0 - KP_9
+Shift_L, Shift_R
+Alt_L, Alt_R
+LCTL, RCTL</property>
                     <property name="margin_top">5</property>
                     <property name="margin_bottom">5</property>
                     <property name="label" translatable="yes">Mapping</property>
diff --git a/data/screenshot.png b/data/screenshot.png
index 3d938488..28634a8c 100644
Binary files a/data/screenshot.png and b/data/screenshot.png differ
diff --git a/data/screenshot.png~ b/data/screenshot.png~
new file mode 100644
index 00000000..b150f2cb
Binary files /dev/null and b/data/screenshot.png~ differ
diff --git a/data/style.css b/data/style.css
index e3a29144..e8947905 100644
--- a/data/style.css
+++ b/data/style.css
@@ -1,5 +1,15 @@
 list entry {
     background-color: transparent;
+    border-radius: 4px;
+}
+
+list button:not(:focus) {
+    border-color: transparent;
+    background-color: transparent;
+}
+
+list button {
+    border-color: transparent;
 }
 
 .button_container {
diff --git a/keymapper/X.py b/keymapper/X.py
index bee28b9e..6c279e64 100644
--- a/keymapper/X.py
+++ b/keymapper/X.py
@@ -50,6 +50,7 @@ class Mapping:
     """
     def __init__(self):
         self._mapping = {}
+        self.changed = False
 
     def __iter__(self):
         """Iterate over tuples of unique keycodes and their character."""
@@ -82,6 +83,8 @@ class Mapping:
                 in result
             }
 
+        self.changed = False
+
     def change(self, previous_keycode, new_keycode, character):
         """Replace the mapping of a keycode with a different one.
 
@@ -100,8 +103,8 @@ class Mapping:
                 # clear previous mapping of that code, because the line
                 # representing that one will now represent a different one.
                 self.clear(previous_keycode)
-            return True
-        return False
+            self.changed = True
+        return self.changed
 
     def clear(self, keycode):
         """Remove a keycode from the mapping.
@@ -112,6 +115,7 @@ class Mapping:
         """
         if self._mapping.get(keycode) is not None:
             del self._mapping[keycode]
+            self.changed = True
 
     def get(self, keycode):
         """Read the character that is mapped to this keycode.
@@ -123,6 +127,10 @@ class Mapping:
         return self._mapping.get(keycode)
 
 
+# one mapping object for the whole application
+mapping = Mapping()
+
+
 def ensure_symlink():
     """Make sure the symlink exists.
 
@@ -276,7 +284,6 @@ def generate_symbols_content(device, preset, mapping):
     preset : string
     mapping : Mapping
     """
-    # TODO test this function
     system_default = 'us'  # TODO get the system default
 
     if len(mapping) == 0:
diff --git a/keymapper/linux.py b/keymapper/linux.py
index 0010cb48..584abac5 100644
--- a/keymapper/linux.py
+++ b/keymapper/linux.py
@@ -120,7 +120,7 @@ def get_devices():
     for device in devices:
         # only keyboard devices
         # https://www.kernel.org/doc/html/latest/input/event-codes.html
-        if not evdev.ecodes.EV_KEY in device.capabilities().keys():
+        if evdev.ecodes.EV_KEY not in device.capabilities().keys():
             continue
 
         usb = device.phys.split('/')[0]
diff --git a/tests/testcases/config.py b/tests/testcases/config.py
index 8bfc1f5d..af9e743a 100644
--- a/tests/testcases/config.py
+++ b/tests/testcases/config.py
@@ -34,7 +34,7 @@ class TestConfig(unittest.TestCase):
     def setUp(self):
         self.mapping = Mapping()
         self.mapping.change(None, 10, 'a')
-        self.mapping.change(None, 11, 'NUM1')
+        self.mapping.change(None, 11, 'KP_1')
         self.mapping.change(None, 12, 3)
         if os.path.exists(tmp):
             shutil.rmtree(tmp)
@@ -59,7 +59,7 @@ class TestConfig(unittest.TestCase):
         with open(get_home_path('device_a', 'preset_b'), 'r') as f:
             content = f.read()
             self.assertIn('key <10> { [ a ] };', content)
-            self.assertIn('key <11> { [ NUM1 ] };', content)
+            self.assertIn('key <11> { [ KP_1 ] };', content)
             self.assertIn('key <12> { [ 3 ] };', content)
 
     def test_generate_content(self):
@@ -80,7 +80,7 @@ class TestConfig(unittest.TestCase):
 
         content = generate_symbols_content('device', 'preset', self.mapping)
         self.assertIn('key <10> { [ a ] };', content)
-        self.assertIn('key <11> { [ NUM1 ] };', content)
+        self.assertIn('key <11> { [ KP_1 ] };', content)
         self.assertIn('key <12> { [ 3 ] };', content)
 
 
diff --git a/tests/testcases/integration.py b/tests/testcases/integration.py
index aab1b993..ed89f592 100644
--- a/tests/testcases/integration.py
+++ b/tests/testcases/integration.py
@@ -32,6 +32,8 @@ import shutil
 gi.require_version('Gtk', '3.0')
 from gi.repository import Gtk
 
+from keymapper.X import mapping
+
 from test import tmp
 
 
@@ -89,6 +91,31 @@ class Integration(unittest.TestCase):
         self.assertIsNotNone(self.window)
         self.assertTrue(self.window.window.get_visible())
 
+    def test_adds_empty_rows(self):
+        rows = len(self.window.get('key_list').get_children())
+        self.assertEqual(rows, 1)
+
+        mapping.change(None, 13, 'a')
+        time.sleep(0.2)
+        gtk_iteration()
+
+        rows = len(self.window.get('key_list').get_children())
+        self.assertEqual(rows, 2)
+
+    def test_rename_and_save(self):
+        mapping.change(None, 14, 'a')
+        self.assertEqual(self.window.selected_preset, 'new preset')
+        self.window.on_save_preset_clicked(None)
+        self.assertEqual(mapping.get(14), 'a')
+
+        mapping.change(None, 14, 'b')
+        self.window.get('preset_name_input').set_text('asdf')
+        self.window.on_save_preset_clicked(None)
+        self.assertEqual(self.window.selected_preset, 'asdf')
+        self.assertTrue(os.path.exists(f'{tmp}/symbols/device_1/asdf'))
+        self.assertTrue(os.path.exists(f'{tmp}/.config/device_1/asdf'))
+        self.assertEqual(mapping.get(14), 'b')
+
     def test_select_device_and_preset(self):
         class FakeDropdown(Gtk.ComboBoxText):
             def __init__(self, name):
diff --git a/tests/testcases/mapping.py b/tests/testcases/mapping.py
index 308074d0..40de4a6d 100644
--- a/tests/testcases/mapping.py
+++ b/tests/testcases/mapping.py
@@ -27,10 +27,12 @@ from keymapper.X import Mapping
 class TestMapping(unittest.TestCase):
     def setUp(self):
         self.mapping = Mapping()
+        self.assertFalse(self.mapping.changed)
 
     def test_change(self):
         # 1 is not assigned yet, ignore it
         self.mapping.change(1, 2, 'a')
+        self.assertTrue(self.mapping.changed)
         self.assertIsNone(self.mapping.get(1))
         self.assertEqual(self.mapping.get(2), 'a')
         self.assertEqual(len(self.mapping), 1)
@@ -58,13 +60,22 @@ class TestMapping(unittest.TestCase):
         self.assertEqual(len(self.mapping), 2)
 
     def test_clear(self):
-        self.mapping.change(None, 10, 'NUM1')
-        self.mapping.change(None, 20, 'NUM2')
-        self.mapping.change(None, 30, 'NUM3')
+        # does nothing
+        self.mapping.clear(40)
+        self.assertFalse(self.mapping.changed)
+
+        self.mapping._mapping[40] = 'b'
+        self.mapping.clear(40)
+        self.assertTrue(self.mapping.changed)
+
+        self.mapping.change(None, 10, 'KP_1')
+        self.assertTrue(self.mapping.changed)
+        self.mapping.change(None, 20, 'KP_2')
+        self.mapping.change(None, 30, 'KP_3')
         self.mapping.clear(20)
-        self.assertEqual(self.mapping.get(10), 'NUM1')
+        self.assertEqual(self.mapping.get(10), 'KP_1')
         self.assertIsNone(self.mapping.get(20))
-        self.assertEqual(self.mapping.get(30), 'NUM3')
+        self.assertEqual(self.mapping.get(30), 'KP_3')
 
     def test_iterate_and_convert(self):
         self.mapping.change(None, 10, 1)