Fix list cursor when item moves off-screen

When a list scrolls or changes in such a way that the cursor item moves
off-screen, the cursor would jump to the closest visible item.

It makes more sense for the cursor to remain on its selected item and
for the list to scroll instead. That way, it is less likely for the user
to perform an action on the wrong list item if they press a key while
the list is changing.

2 files changed, 8 insertions, 4 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3cffe55..5f6df89 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -21,6 +21,7 @@ Procedure when bumping the version number:
 
 ### Fixed
 - Cursor being visible through popups
+- Cursor in lists when highlighted item moves off-screen
 
 ## v0.4.0 - 2022-09-01
 
diff --git a/src/ui/widgets/list.rs b/src/ui/widgets/list.rs
index 6a586a1..8df110c 100644
--- a/src/ui/widgets/list.rs
+++ b/src/ui/widgets/list.rs
@@ -1,5 +1,3 @@
-// TODO Fix scrolling by focusing on the cursor like in chat::tree
-
 use std::sync::Arc;
 
 use async_trait::async_trait;
@@ -36,7 +34,10 @@ impl<Id> Cursor<Id> {
 #[derive(Debug)]
 struct InnerListState<Id> {
     rows: Vec<Option<Id>>,
+
+    /// Offset of the first line visible on the screen.
     offset: usize,
+
     cursor: Option<Cursor<Id>>,
     make_cursor_visible: bool,
 }
@@ -47,7 +48,7 @@ impl<Id> InnerListState<Id> {
             rows: vec![],
             offset: 0,
             cursor: None,
-            make_cursor_visible: false,
+            make_cursor_visible: true,
         }
     }
 }
@@ -172,7 +173,7 @@ impl<Id: Clone + Eq> InnerListState<Id> {
             self.clamp_scrolling(height);
             self.move_cursor_to_make_it_visible(height);
         }
-        self.make_cursor_visible = false;
+        self.make_cursor_visible = true;
     }
 }
 
@@ -190,11 +191,13 @@ impl<Id> ListState<Id> {
     pub fn scroll_up(&mut self, amount: usize) {
         let mut guard = self.0.lock();
         guard.offset = guard.offset.saturating_sub(amount);
+        guard.make_cursor_visible = false;
     }
 
     pub fn scroll_down(&mut self, amount: usize) {
         let mut guard = self.0.lock();
         guard.offset = guard.offset.saturating_add(amount);
+        guard.make_cursor_visible = false;
     }
 }