diff --git a/src/tui/app/app.rs b/src/tui/app/app.rs
index d3d3644..9ebf397 100644
--- a/src/tui/app/app.rs
+++ b/src/tui/app/app.rs
@@ -369,7 +369,7 @@ mod tests {
             Some(0)
         );
 
-        app.increment_selection();
+        app.increment_selection(Delta::Line);
         assert_eq!(app.selection.active, Category::Artist);
         assert_eq!(app.selection.artist.state.list.selected(), Some(1));
         assert_eq!(app.selection.artist.album.state.list.selected(), Some(0));
@@ -387,7 +387,7 @@ mod tests {
             Some(0)
         );
 
-        app.increment_selection();
+        app.increment_selection(Delta::Line);
         assert_eq!(app.selection.active, Category::Album);
         assert_eq!(app.selection.artist.state.list.selected(), Some(1));
         assert_eq!(app.selection.artist.album.state.list.selected(), Some(1));
@@ -405,7 +405,7 @@ mod tests {
             Some(0)
         );
 
-        app.increment_selection();
+        app.increment_selection(Delta::Line);
         assert_eq!(app.selection.active, Category::Track);
         assert_eq!(app.selection.artist.state.list.selected(), Some(1));
         assert_eq!(app.selection.artist.album.state.list.selected(), Some(1));
@@ -423,7 +423,7 @@ mod tests {
             Some(1)
         );
 
-        app.decrement_selection();
+        app.decrement_selection(Delta::Line);
         assert_eq!(app.selection.active, Category::Track);
         assert_eq!(app.selection.artist.state.list.selected(), Some(1));
         assert_eq!(app.selection.artist.album.state.list.selected(), Some(1));
@@ -432,7 +432,7 @@ mod tests {
             Some(0)
         );
 
-        app.increment_selection();
+        app.increment_selection(Delta::Line);
         app.decrement_category();
         assert_eq!(app.selection.active, Category::Album);
         assert_eq!(app.selection.artist.state.list.selected(), Some(1));
@@ -442,7 +442,7 @@ mod tests {
             Some(1)
         );
 
-        app.decrement_selection();
+        app.decrement_selection(Delta::Line);
         assert_eq!(app.selection.active, Category::Album);
         assert_eq!(app.selection.artist.state.list.selected(), Some(1));
         assert_eq!(app.selection.artist.album.state.list.selected(), Some(0));
@@ -451,7 +451,7 @@ mod tests {
             Some(0)
         );
 
-        app.increment_selection();
+        app.increment_selection(Delta::Line);
         app.decrement_category();
         assert_eq!(app.selection.active, Category::Artist);
         assert_eq!(app.selection.artist.state.list.selected(), Some(1));
@@ -461,7 +461,7 @@ mod tests {
             Some(0)
         );
 
-        app.decrement_selection();
+        app.decrement_selection(Delta::Line);
         assert_eq!(app.selection.active, Category::Artist);
         assert_eq!(app.selection.artist.state.list.selected(), Some(0));
         assert_eq!(app.selection.artist.album.state.list.selected(), Some(0));
@@ -471,9 +471,9 @@ mod tests {
         );
 
         app.increment_category();
-        app.increment_selection();
+        app.increment_selection(Delta::Line);
         app.decrement_category();
-        app.decrement_selection();
+        app.decrement_selection(Delta::Line);
         app.decrement_category();
         assert_eq!(app.selection.active, Category::Artist);
         assert_eq!(app.selection.artist.state.list.selected(), Some(0));
@@ -500,13 +500,13 @@ mod tests {
         app.increment_category();
         app.increment_category();
 
-        app.increment_selection();
+        app.increment_selection(Delta::Line);
         assert_eq!(app.selection.active, Category::Track);
         assert_eq!(app.selection.artist.state.list.selected(), Some(0));
         assert_eq!(app.selection.artist.album.state.list.selected(), Some(0));
         assert_eq!(app.selection.artist.album.track.state.list.selected(), None);
 
-        app.decrement_selection();
+        app.decrement_selection(Delta::Line);
         assert_eq!(app.selection.active, Category::Track);
         assert_eq!(app.selection.artist.state.list.selected(), Some(0));
         assert_eq!(app.selection.artist.album.state.list.selected(), Some(0));
@@ -528,13 +528,13 @@ mod tests {
 
         app.increment_category();
 
-        app.increment_selection();
+        app.increment_selection(Delta::Line);
         assert_eq!(app.selection.active, Category::Album);
         assert_eq!(app.selection.artist.state.list.selected(), Some(0));
         assert_eq!(app.selection.artist.album.state.list.selected(), None);
         assert_eq!(app.selection.artist.album.track.state.list.selected(), None);
 
-        app.decrement_selection();
+        app.decrement_selection(Delta::Line);
         assert_eq!(app.selection.active, Category::Album);
         assert_eq!(app.selection.artist.state.list.selected(), Some(0));
         assert_eq!(app.selection.artist.album.state.list.selected(), None);
@@ -542,13 +542,13 @@ mod tests {
 
         app.increment_category();
 
-        app.increment_selection();
+        app.increment_selection(Delta::Line);
         assert_eq!(app.selection.active, Category::Track);
         assert_eq!(app.selection.artist.state.list.selected(), Some(0));
         assert_eq!(app.selection.artist.album.state.list.selected(), None);
         assert_eq!(app.selection.artist.album.track.state.list.selected(), None);
 
-        app.decrement_selection();
+        app.decrement_selection(Delta::Line);
         assert_eq!(app.selection.active, Category::Track);
         assert_eq!(app.selection.artist.state.list.selected(), Some(0));
         assert_eq!(app.selection.artist.album.state.list.selected(), None);
@@ -565,13 +565,13 @@ mod tests {
         assert_eq!(app.selection.artist.album.state.list.selected(), None);
         assert_eq!(app.selection.artist.album.track.state.list.selected(), None);
 
-        app.increment_selection();
+        app.increment_selection(Delta::Line);
         assert_eq!(app.selection.active, Category::Artist);
         assert_eq!(app.selection.artist.state.list.selected(), None);
         assert_eq!(app.selection.artist.album.state.list.selected(), None);
         assert_eq!(app.selection.artist.album.track.state.list.selected(), None);
 
-        app.decrement_selection();
+        app.decrement_selection(Delta::Line);
         assert_eq!(app.selection.active, Category::Artist);
         assert_eq!(app.selection.artist.state.list.selected(), None);
         assert_eq!(app.selection.artist.album.state.list.selected(), None);
@@ -579,13 +579,13 @@ mod tests {
 
         app.increment_category();
 
-        app.increment_selection();
+        app.increment_selection(Delta::Line);
         assert_eq!(app.selection.active, Category::Album);
         assert_eq!(app.selection.artist.state.list.selected(), None);
         assert_eq!(app.selection.artist.album.state.list.selected(), None);
         assert_eq!(app.selection.artist.album.track.state.list.selected(), None);
 
-        app.decrement_selection();
+        app.decrement_selection(Delta::Line);
         assert_eq!(app.selection.active, Category::Album);
         assert_eq!(app.selection.artist.state.list.selected(), None);
         assert_eq!(app.selection.artist.album.state.list.selected(), None);
@@ -593,13 +593,13 @@ mod tests {
 
         app.increment_category();
 
-        app.increment_selection();
+        app.increment_selection(Delta::Line);
         assert_eq!(app.selection.active, Category::Track);
         assert_eq!(app.selection.artist.state.list.selected(), None);
         assert_eq!(app.selection.artist.album.state.list.selected(), None);
         assert_eq!(app.selection.artist.album.track.state.list.selected(), None);
 
-        app.decrement_selection();
+        app.decrement_selection(Delta::Line);
         assert_eq!(app.selection.active, Category::Track);
         assert_eq!(app.selection.artist.state.list.selected(), None);
         assert_eq!(app.selection.artist.album.state.list.selected(), None);
diff --git a/src/tui/app/selection.rs b/src/tui/app/selection.rs
index 1b5db4f..129275f 100644
--- a/src/tui/app/selection.rs
+++ b/src/tui/app/selection.rs
@@ -452,17 +452,17 @@ mod tests {
         let mut sel = TrackSelection::initialise(tracks);
         assert_eq!(sel.state.list.selected(), Some(0));
 
-        sel.decrement(tracks);
+        sel.decrement(tracks, Delta::Line);
         assert_eq!(sel.state.list.selected(), Some(0));
 
-        sel.increment(tracks);
+        sel.increment(tracks, Delta::Line);
         assert_eq!(sel.state.list.selected(), Some(1));
 
-        sel.decrement(tracks);
+        sel.decrement(tracks, Delta::Line);
         assert_eq!(sel.state.list.selected(), Some(0));
 
         for _ in 0..(tracks.len() + 5) {
-            sel.increment(tracks);
+            sel.increment(tracks, Delta::Line);
         }
         assert_eq!(sel.state.list.selected(), Some(tracks.len() - 1));
 
@@ -474,7 +474,7 @@ mod tests {
 
         // Re-initialise out-of-bounds.
         let mut expected = sel.clone();
-        expected.decrement(tracks);
+        expected.decrement(tracks, Delta::Line);
         let active_track = ActiveTrack::get(tracks, &sel);
         sel.reinitialise(&tracks[..(tracks.len() - 1)], active_track);
         assert_eq!(sel, expected);
@@ -484,13 +484,6 @@ mod tests {
         let active_track = ActiveTrack::get(tracks, &sel);
         sel.reinitialise(&[], active_track);
         assert_eq!(sel, expected);
-
-        // Artifical test case to verify upper limit.
-        sel.state.list.select(Some(std::usize::MAX));
-        assert_eq!(sel.state.list.selected(), Some(std::usize::MAX));
-
-        sel.increment(&[]);
-        assert_eq!(sel.state.list.selected(), Some(std::usize::MAX));
     }
 
     #[test]
@@ -505,35 +498,35 @@ mod tests {
         assert_eq!(sel.state.list.selected(), Some(0));
         assert_eq!(sel.track.state.list.selected(), Some(0));
 
-        sel.increment_track(albums);
+        sel.increment_track(albums, Delta::Line);
         assert_eq!(sel.state.list.selected(), Some(0));
         assert_eq!(sel.track.state.list.selected(), Some(1));
 
         // Verify that decrement that doesn't change index does not reset track.
-        sel.decrement(albums);
+        sel.decrement(albums, Delta::Line);
         assert_eq!(sel.state.list.selected(), Some(0));
         assert_eq!(sel.track.state.list.selected(), Some(1));
 
-        sel.increment(albums);
+        sel.increment(albums, Delta::Line);
         assert_eq!(sel.state.list.selected(), Some(1));
         assert_eq!(sel.track.state.list.selected(), Some(0));
 
-        sel.decrement(albums);
+        sel.decrement(albums, Delta::Line);
         assert_eq!(sel.state.list.selected(), Some(0));
         assert_eq!(sel.track.state.list.selected(), Some(0));
 
         for _ in 0..(albums.len() + 5) {
-            sel.increment(albums);
+            sel.increment(albums, Delta::Line);
         }
         assert_eq!(sel.state.list.selected(), Some(albums.len() - 1));
         assert_eq!(sel.track.state.list.selected(), Some(0));
 
-        sel.increment_track(albums);
+        sel.increment_track(albums, Delta::Line);
         assert_eq!(sel.state.list.selected(), Some(albums.len() - 1));
         assert_eq!(sel.track.state.list.selected(), Some(1));
 
         // Verify that increment that doesn't change index does not reset track.
-        sel.increment(albums);
+        sel.increment(albums, Delta::Line);
         assert_eq!(sel.state.list.selected(), Some(albums.len() - 1));
         assert_eq!(sel.track.state.list.selected(), Some(1));
 
@@ -545,7 +538,7 @@ mod tests {
 
         // Re-initialise out-of-bounds.
         let mut expected = sel.clone();
-        expected.decrement(albums);
+        expected.decrement(albums, Delta::Line);
         let active_album = ActiveAlbum::get(albums, &sel);
         sel.reinitialise(&albums[..(albums.len() - 1)], active_album);
         assert_eq!(sel, expected);
@@ -555,16 +548,6 @@ mod tests {
         let active_album = ActiveAlbum::get(albums, &sel);
         sel.reinitialise(&[], active_album);
         assert_eq!(sel, expected);
-
-        // Artifical test case to verify upper limit.
-        sel.state.list.select(Some(std::usize::MAX));
-        sel.track.state.list.select(Some(1));
-        assert_eq!(sel.state.list.selected(), Some(std::usize::MAX));
-        assert_eq!(sel.track.state.list.selected(), Some(1));
-
-        sel.increment(&[]);
-        assert_eq!(sel.state.list.selected(), Some(std::usize::MAX));
-        assert_eq!(sel.track.state.list.selected(), Some(1));
     }
 
     #[test]
@@ -579,35 +562,35 @@ mod tests {
         assert_eq!(sel.state.list.selected(), Some(0));
         assert_eq!(sel.album.state.list.selected(), Some(0));
 
-        sel.increment_album(artists);
+        sel.increment_album(artists, Delta::Line);
         assert_eq!(sel.state.list.selected(), Some(0));
         assert_eq!(sel.album.state.list.selected(), Some(1));
 
         // Verify that decrement that doesn't change index does not reset album.
-        sel.decrement(artists);
+        sel.decrement(artists, Delta::Line);
         assert_eq!(sel.state.list.selected(), Some(0));
         assert_eq!(sel.album.state.list.selected(), Some(1));
 
-        sel.increment(artists);
+        sel.increment(artists, Delta::Line);
         assert_eq!(sel.state.list.selected(), Some(1));
         assert_eq!(sel.album.state.list.selected(), Some(0));
 
-        sel.decrement(artists);
+        sel.decrement(artists, Delta::Line);
         assert_eq!(sel.state.list.selected(), Some(0));
         assert_eq!(sel.album.state.list.selected(), Some(0));
 
         for _ in 0..(artists.len() + 5) {
-            sel.increment(artists);
+            sel.increment(artists, Delta::Line);
         }
         assert_eq!(sel.state.list.selected(), Some(artists.len() - 1));
         assert_eq!(sel.album.state.list.selected(), Some(0));
 
-        sel.increment_album(artists);
+        sel.increment_album(artists, Delta::Line);
         assert_eq!(sel.state.list.selected(), Some(artists.len() - 1));
         assert_eq!(sel.album.state.list.selected(), Some(1));
 
         // Verify that increment that doesn't change index does not reset album.
-        sel.increment(artists);
+        sel.increment(artists, Delta::Line);
         assert_eq!(sel.state.list.selected(), Some(artists.len() - 1));
         assert_eq!(sel.album.state.list.selected(), Some(1));
 
@@ -619,7 +602,7 @@ mod tests {
 
         // Re-initialise out-of-bounds.
         let mut expected = sel.clone();
-        expected.decrement(artists);
+        expected.decrement(artists, Delta::Line);
         let active_artist = ActiveArtist::get(artists, &sel);
         sel.reinitialise(&artists[..(artists.len() - 1)], active_artist);
         assert_eq!(sel, expected);
@@ -629,15 +612,5 @@ mod tests {
         let active_artist = ActiveArtist::get(artists, &sel);
         sel.reinitialise(&[], active_artist);
         assert_eq!(sel, expected);
-
-        // Artifical test case to verify upper limit.
-        sel.state.list.select(Some(std::usize::MAX));
-        sel.album.state.list.select(Some(1));
-        assert_eq!(sel.state.list.selected(), Some(std::usize::MAX));
-        assert_eq!(sel.album.state.list.selected(), Some(1));
-
-        sel.increment(&[]);
-        assert_eq!(sel.state.list.selected(), Some(std::usize::MAX));
-        assert_eq!(sel.album.state.list.selected(), Some(1));
     }
 }
diff --git a/src/tui/ui.rs b/src/tui/ui.rs
index d7b78ba..693959f 100644
--- a/src/tui/ui.rs
+++ b/src/tui/ui.rs
@@ -513,7 +513,11 @@ impl IUi for Ui {
 
 #[cfg(test)]
 mod tests {
-    use crate::tui::{app::app::AppPublic, testmod::COLLECTION, tests::terminal};
+    use crate::tui::{
+        app::{app::AppPublic, selection::Delta},
+        testmod::COLLECTION,
+        tests::terminal,
+    };
 
     use super::*;
 
@@ -567,14 +571,14 @@ mod tests {
         // Change the track (which has a different track format).
         selection.increment_category();
         selection.increment_category();
-        selection.increment_selection(artists);
+        selection.increment_selection(artists, Delta::Line);
 
         draw_test_suite(artists, &mut selection);
 
         // Change the artist (which has a multi-link entry).
         selection.decrement_category();
         selection.decrement_category();
-        selection.increment_selection(artists);
+        selection.increment_selection(artists, Delta::Line);
 
         draw_test_suite(artists, &mut selection);
     }