Hide off-screen scrolling columns and stop boundary focus jumps

src/layout_engine/engine.rs

@@ -702,6 +702,12 @@ impl LayoutEngine {
             if let Some(prev_wid) = previous_selection {
                 let _ = self.workspace_tree_mut(ws_id).select_window(layout, prev_wid);
             }
+            // In scrolling layout, don't jump to adjacent displays at the
+            // boundary. Off-screen columns are intentionally hidden, so
+            // cross-display focus here would select a hidden window.
+            if matches!(self.workspace_tree(ws_id), LayoutSystemKind::Scrolling(_)) {
+                return EventResponse::default();
+            }
             if let Some(new_space) = self.next_space_for_direction(
                 space,
                 direction,

src/layout_engine/systems/scrolling.rs

@@ -765,7 +765,19 @@ impl LayoutSystem for ScrollingLayoutSystem {
                 .copied()
                 .unwrap_or((tiling.size.width * ratio).max(1.0));
             let start = column_starts.get(col_idx).copied().unwrap_or(0.0);
-            let x = anchor_x + start - offset;
+            let mut x = anchor_x + start - offset;
+            // Hide off-screen columns by clamping them to 1px visible at the
+            // screen edge. This prevents cross-app Z-order issues since
+            // macOS can't reorder other apps' windows via SLSOrderWindow.
+            let visible_left = tiling.origin.x;
+            let visible_right = tiling.origin.x + tiling.size.width;
+            if x + column_width <= visible_left {
+                // Column is fully off-screen left: hide just past the edge
+                x = visible_left - column_width;
+            } else if x >= visible_right {
+                // Column is fully off-screen right: hide just past the edge
+                x = visible_right;
+            }
             if col.windows.is_empty() {
                 continue;
             }