From f66c992ad88324d0495db0fae606a82d7031f360 Mon Sep 17 00:00:00 2001
From: Kevin Ansfield <kevin@lookingsideways.co.uk>
Date: Thu, 21 Oct 2021 13:37:38 +0100
Subject: [PATCH] Fixed design preview remembering scroll position when
 changing page

refs https://github.com/TryGhost/Team/issues/1149

- added a `@pageId` argument to `<GhHtmlIframe>`, if that value is different at the point of swapping iframes after re-rendering it will reset the scroll position instead of copying it from the to-be-hidden iframe
- assigned `themeManagement.previewType` to `@pageId` so that it changes when switching between homepage and post previews
---
 ghost/admin/app/components/gh-html-iframe.js        | 9 ++++++++-
 ghost/admin/app/templates/settings/design/index.hbs | 2 +-
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/ghost/admin/app/components/gh-html-iframe.js b/ghost/admin/app/components/gh-html-iframe.js
index fd29a7a4e5..0b84c24c3f 100644
--- a/ghost/admin/app/components/gh-html-iframe.js
+++ b/ghost/admin/app/components/gh-html-iframe.js
@@ -62,7 +62,14 @@ export default class GhHtmlIframeComponent extends Component {
         window.clearTimeout(this.swapTimeout);
 
         if (this.iframes.indexOf(renderedIframe) !== this.renderedIframe) {
-            this.iframes[this.toRenderIframe].contentDocument.body.scrollTop = this.iframes[this.renderedIframe].contentDocument.body.scrollTop;
+            let newScrollTop = this.iframes[this.renderedIframe].contentDocument.body.scrollTop;
+
+            if (this._lastPageId !== this.args.pageId) {
+                newScrollTop = 0;
+            }
+            this._lastPageId = this.args.pageId;
+
+            this.iframes[this.toRenderIframe].contentDocument.body.scrollTop = newScrollTop;
             this.iframes[this.toRenderIframe].style = this.visibleIframeStyle;
             this.renderedIframe = this.toRenderIframe;
             this.toRenderIframe = this.toRenderIframe === 0 ? 1 : 0;
diff --git a/ghost/admin/app/templates/settings/design/index.hbs b/ghost/admin/app/templates/settings/design/index.hbs
index 96f3eed6b6..e661fc1d18 100644
--- a/ghost/admin/app/templates/settings/design/index.hbs
+++ b/ghost/admin/app/templates/settings/design/index.hbs
@@ -50,7 +50,7 @@
             {{/if}}
             <div class="{{if this.isMobilePreview "gh-pe-mobile-bezel" "gh-browserpreview-iframecontainer"}}">
                 <div class="{{if this.isMobilePreview "gh-pe-mobile-screen"}}">
-                    <GhHtmlIframe class={{if this.isMobilePreview "gh-post-preview-iframe" "site-frame"}} @html={{this.themeManagement.previewHtml}} />
+                    <GhHtmlIframe class={{if this.isMobilePreview "gh-post-preview-iframe" "site-frame"}} @html={{this.themeManagement.previewHtml}} @pageId={{this.themeManagement.previewType}} />
                 </div>
             </div>
         </div>