Do not trigger ScrollButton event unless clicked (#6938)

panel/layout/feed.py

@@ -195,7 +195,7 @@ def _process_event(self, event: ScrollButtonClick) -> None:
  n_visible = self.visible_range[-1] - self.visible_range[0]
  with edit_readonly(self):
  # plus one to center on the last object
- self.visible_range = (max(n - n_visible + 1, 0), n)
+ self.visible_range = (min(max(n - n_visible + 1, 0), n), n)
 
  with param.discard_events(self):
  # reset the buffers and loaded objects

panel/models/column.ts

@@ -1,6 +1,14 @@
-import {Column as BkColumn, ColumnView as BkColumnView} from "@bokehjs/models/layouts/column"
-import * as DOM from "@bokehjs/core/dom"
+import {ModelEvent} from "@bokehjs/core/bokeh_events"
+import {div} from "@bokehjs/core/dom"
 import type * as p from "@bokehjs/core/properties"
+import type {EventCallback} from "@bokehjs/model"
+import {Column as BkColumn, ColumnView as BkColumnView} from "@bokehjs/models/layouts/column"
+
+export class ScrollButtonClick extends ModelEvent {
+ static {
+ this.prototype.event_name = "scroll_button_click"
+ }
+}
 
 export class ColumnView extends BkColumnView {
  declare model: Column
@@ -62,14 +70,15 @@ export class ColumnView extends BkColumnView {
 
  override render(): void {
  super.render()
- this.scroll_down_button_el = DOM.createElement("div", {class: "scroll-button"})
+ this.scroll_down_button_el = div({class: "scroll-button"})
  this.shadow_el.appendChild(this.scroll_down_button_el)
  this.el.addEventListener("scroll", () => {
  this.record_scroll_position()
  this.toggle_scroll_button()
  })
  this.scroll_down_button_el.addEventListener("click", () => {
  this.scroll_to_latest()
+ this.model.trigger_event(new ScrollButtonClick())
  })
  }
 
@@ -118,4 +127,8 @@ export class Column extends BkColumn {
  view_latest: [Bool, false],
  }))
  }
+
+ on_click(callback: EventCallback<ScrollButtonClick>): void {
+ this.on_event(ScrollButtonClick, callback)
+ }
 }

panel/models/feed.ts

@@ -2,14 +2,6 @@ import {Column, ColumnView} from "./column"
 import type * as p from "@bokehjs/core/properties"
 import {build_views} from "@bokehjs/core/build_views"
 import type {UIElementView} from "@bokehjs/models/ui/ui_element"
-import {ModelEvent} from "@bokehjs/core/bokeh_events"
-import type {EventCallback} from "@bokehjs/model"
-
-export class ScrollButtonClick extends ModelEvent {
- static {
- this.prototype.event_name = "scroll_button_click"
- }
-}
 
 export class FeedView extends ColumnView {
  declare model: Feed
@@ -89,21 +81,13 @@ export class FeedView extends ColumnView {
  return created
  }
 
- override scroll_to_latest(emit_event: boolean = true): void {
- if (emit_event) {
- this.model.trigger_event(new ScrollButtonClick())
- }
- super.scroll_to_latest()
- }
-
  override trigger_auto_scroll(): void {
  const limit = this.model.auto_scroll_limit
  const within_limit = this.distance_from_latest <= limit
  if (limit == 0 || !within_limit) {
  return
  }
-
- this.scroll_to_latest(false)
+ this.scroll_to_latest()
  }
 }
 
@@ -132,8 +116,4 @@ export class Feed extends Column {
  visible_children: [List(Str), []],
  }))
  }
-
- on_click(callback: EventCallback<ScrollButtonClick>): void {
- this.on_event(ScrollButtonClick, callback)
- }
 }