fix(epg): close the programme popover when the window drops its block

Review follow-up (Codex): the ribbon window can remove a focused narrow
block on scroll, and a removed node fires no focusout, so the fixed
tooltip kept showing a programme no longer on screen. The popover is now
a linkedSignal over the rendered items that keeps its state only while
its block (by key) is still rendered.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

libs/ui/epg/src/lib/epg-timeline/epg-timeline-track.component.spec.ts

@@ -82,11 +82,52 @@ describe('EpgTimelineTrackComponent', () => {
         expect(component.popover()).toBeNull();
     });
 
+    // The ribbon window can remove a focused block on scroll; a removed node
+    // fires no focusout, so the popover must follow the rendered items.
+    it('closes the popover when its block leaves the rendered items', () => {
+        const item = renderBlock({ tier: 'narrow' });
+        const other = renderBlock({ key: 'k2', tier: 'narrow' });
+        fixture.componentRef.setInput('items', [item, other]);
+        fixture.detectChanges();
+        component.onBlockEnter(item, {
+            currentTarget: {
+                getBoundingClientRect: () => ({
+                    left: 100,
+                    width: 40,
+                    top: 60,
+                    bottom: 200,
+                }),
+            },
+        } as unknown as Event);
+
+        fixture.componentRef.setInput('items', [item]);
+        fixture.detectChanges();
+        expect(component.popover()?.key).toBe('k1');
+        expect(
+            (fixture.nativeElement as HTMLElement).querySelector(
+                '[role="tooltip"]'
+            )
+        ).not.toBeNull();
+
+        fixture.componentRef.setInput('items', [other]);
+        fixture.detectChanges();
+        expect(component.popover()).toBeNull();
+        expect(
+            (fixture.nativeElement as HTMLElement).querySelector(
+                '[role="tooltip"]'
+            )
+        ).toBeNull();
+    });
+
     it('never shows a popover for a wide block', () => {
         const item = renderBlock({ tier: 'wide' });
         component.onBlockEnter(item, {
             currentTarget: {
-                getBoundingClientRect: () => ({ left: 0, width: 200, bottom: 0 }),
+                getBoundingClientRect: () => ({
+                    left: 0,
+                    width: 200,
+                    bottom: 0,
+                }),
             },
         } as unknown as Event);
         expect(component.popover()).toBeNull();

libs/ui/epg/src/lib/epg-timeline/epg-timeline-track.component.ts

@@ -5,8 +5,8 @@ import {
     computed,
     HostBinding,
     input,
+    linkedSignal,
     output,
-    signal,
 } from '@angular/core';
 import { MatIcon } from '@angular/material/icon';
 import { EpgProgram } from '@iptvnator/shared/interfaces';
@@ -22,6 +22,8 @@ import {
 } from './epg-timeline.utils';
 
 interface PopoverState {
+    /** The render item it describes. */
+    readonly key: string;
     readonly title: string;
     readonly desc: string | null;
     readonly startMs: number;
@@ -60,7 +62,20 @@ export class EpgTimelineTrackComponent {
     readonly infoClick = output<TimelineBlock>();
     readonly groupExpand = output<TimelineRenderGroup>();
 
-    readonly popover = signal<PopoverState | null>(null);
+    /**
+     * Cleared when its block leaves the rendered items: the ribbon window can
+     * remove a focused block on scroll, and a removed node fires no
+     * `focusout`, so the tooltip would stay on a programme no longer shown.
+     */
+    readonly popover = linkedSignal<TimelineRenderItem[], PopoverState | null>({
+        source: this.items,
+        computation: (items, previous) => {
+            const shown = previous?.value;
+            return shown && items.some((item) => item.key === shown.key)
+                ? shown
+                : null;
+        },
+    });
 
     @HostBinding('style.width.px') get hostWidth(): number {
         return this.trackWidthPx();
@@ -116,6 +131,7 @@ export class EpgTimelineTrackComponent {
         const below = rect.bottom + 8;
         const flipAbove = below + estHeight > window.innerHeight;
         this.popover.set({
+            key: item.key,
             title: item.block.program.title,
             desc: item.block.program.desc,
             startMs: item.block.startMs,
@@ -128,9 +144,7 @@ export class EpgTimelineTrackComponent {
                     rect.left + rect.width / 2 - width / 2
                 )
             ),
-            top: flipAbove
-                ? Math.max(12, rect.top - estHeight - 8)
-                : below,
+            top: flipAbove ? Math.max(12, rect.top - estHeight - 8) : below,
         });
     }