Ensure Feed maintains scroll position (#6984)

panel/models/column.ts

@@ -12,6 +12,7 @@ export class ScrollButtonClick extends ModelEvent {
 
 export class ColumnView extends BkColumnView {
   declare model: Column
+  _updating: boolean = false
 
   scroll_down_button_el: HTMLElement
 
@@ -30,6 +31,9 @@ export class ColumnView extends BkColumnView {
   }
 
   scroll_to_position(): void {
+    if (this._updating) {
+      return
+    }
     requestAnimationFrame(() => {
       this.el.scrollTo({top: this.model.scroll_position, behavior: "instant"})
     })
@@ -56,7 +60,9 @@ export class ColumnView extends BkColumnView {
   }
 
   record_scroll_position(): void {
+    this._updating = true
     this.model.scroll_position = Math.round(this.el.scrollTop)
+    this._updating = false
   }
 
   toggle_scroll_button(): void {

panel/models/feed.ts

@@ -5,9 +5,9 @@ import type {UIElementView} from "@bokehjs/models/ui/ui_element"
 
 export class FeedView extends ColumnView {
   declare model: Feed
-
   _intersection_observer: IntersectionObserver
   _last_visible: UIElementView | null
+  _lock: any = null
   _sync: boolean
 
   override initialize(): void {
@@ -54,10 +54,19 @@ export class FeedView extends ColumnView {
   }
 
   override async update_children(): Promise<void> {
+    const last = this._last_visible
+    const scroll_top = this.el.scrollTop
+    const before_offset = last?.el.offsetTop || 0
     this._sync = false
     await super.update_children()
     this._sync = true
-    this._last_visible?.el.scrollIntoView(true)
+    requestAnimationFrame(() => {
+      const after_offset = last?.el.offsetTop || 0
+      const offset = (after_offset-before_offset)
+      if (offset > 0) {
+        this.el.scrollTo({top: scroll_top + offset, behavior: "instant"})
+      }
+    })
   }
 
   override async build_child_views(): Promise<UIElementView[]> {