sl0p: don't let hover steal focus while typing into a rename prompt

Reported after double-click-to-rename landed: rename one pane, then hovering
over other panes puts them in 'edit title' state too.

Cause is focus_follows_mouse, not the rename itself. RenamePane is a CLIENT
mode that acts on whatever pane is ACTIVE, so with focus-follows-mouse enabled
every pane the mouse passes over becomes active and inherits the prompt. The
double-click entry point just made it easy to hit, since you finish the
gesture with the mouse sitting on a pane frame.

Focus-follows-mouse is now suppressed for a client that is in a modal
text-entry mode: RenamePane, RenameTab, EnterSearch or Prompt. Those all act
on the active pane/tab, so moving focus underneath them is never what the user
meant. Keyboard focus movement is untouched.

Baselines held: zellij-server 1429/30.

1 files changed, 22 insertions, 1 deletions

diff --git a/zellij-server/src/tab/mouse_handler.rs b/zellij-server/src/tab/mouse_handler.rs
index 3e063824..7a329e4b 100644
--- a/zellij-server/src/tab/mouse_handler.rs
+++ b/zellij-server/src/tab/mouse_handler.rs
@@ -506,7 +506,10 @@ impl MouseHandler {
             frame_double_click,
             pinned_selectable,
             pinned_unselectable,
-            focus_follows_mouse: tab.focus_follows_mouse,
+            // suppressed while typing into a rename/search prompt, so hovering
+            // does not drag the prompt onto another pane
+            focus_follows_mouse: tab.focus_follows_mouse
+                && !tab.client_is_in_text_entry_mode(client_id),
             mouse_click_through: tab.mouse_click_through,
             mouse_scroll_resize: tab.mouse_scroll_resize,
         })
@@ -1945,6 +1948,24 @@ mod tests {
     }
 
     #[test]
+    fn hover_does_not_move_focus_when_focus_follows_mouse_is_suppressed() {
+        // Tab suppresses focus_follows_mouse while a client is typing into a
+        // rename/search prompt. Without this, hovering after renaming a pane
+        // drags the prompt onto every pane the mouse touches.
+        let mut ctx = mouse_event_context(false);
+        ctx.active_pane_id = Some(PaneId::Terminal(2));
+        ctx.pane_id_at_position = Some(PaneId::Terminal(1));
+        ctx.focus_follows_mouse = false;
+        let event = MouseEvent::new_left_motion_event(Position::new(3, 3));
+        let action = MouseHandler::determine_mouse_action(&event, &ctx).unwrap();
+        assert!(
+            !matches!(action, MouseAction::FocusOnHover { .. }),
+            "must not steal focus on hover, got {:?}",
+            action
+        );
+    }
+
+    #[test]
     fn a_real_double_click_sequence_is_detected() {
         // REGRESSION: a double-click is press/release/press/release. An earlier
         // version reset the tracker on any event that was not a frame press,