[LyX/master] When splitting a bufferview, keep the scrollbar position

[Jean-Marc Lasgouttes]

commit 100e759f17e8abad66c7923e1737a7f41e8e5ca2
Author: Jean-Marc Lasgouttes <lasgouttes at lyx.org>
Date:   Mon Sep 4 11:26:55 2023 +0200

    When splitting a bufferview, keep the scrollbar position
    
    This is actually better thean making sure that the cursor is visible.
    
    Fixes bug #12689.
---
 src/BufferView.cpp           |    8 ++++++++
 src/BufferView.h             |    3 +++
 src/frontends/qt/GuiView.cpp |    4 ++--
 3 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/src/BufferView.cpp b/src/BufferView.cpp
index 879beb0..ad534ea 100644
--- a/src/BufferView.cpp
+++ b/src/BufferView.cpp
@@ -337,6 +337,14 @@ BufferView::~BufferView()
 }
 
 
+void BufferView::copySettingsFrom(BufferView const & bv)
+{
+	setCursor(bv.cursor());
+	d->anchor_pit_ = bv.d->anchor_pit_;
+	d->anchor_ypos_ = bv.d->anchor_ypos_;
+}
+
+
 int BufferView::defaultMargin() const
 {
 	// The value used to be hardcoded to 10
diff --git a/src/BufferView.h b/src/BufferView.h
index f816eda..d239fdd 100644
--- a/src/BufferView.h
+++ b/src/BufferView.h
@@ -108,6 +108,9 @@ public:
 	Buffer & buffer();
 	Buffer const & buffer() const;
 
+	/// Copy cursor and vertical offset information from \c bv
+	void copySettingsFrom(BufferView const & bv);
+
 	///
 	void setFullScreen(bool full_screen) { full_screen_ = full_screen; }
 
diff --git a/src/frontends/qt/GuiView.cpp b/src/frontends/qt/GuiView.cpp
index c9a9ff8..3723afe 100644
--- a/src/frontends/qt/GuiView.cpp
+++ b/src/frontends/qt/GuiView.cpp
@@ -4879,8 +4879,8 @@ void GuiView::dispatch(FuncRequest const & cmd, DispatchResult & dr)
 			TabWorkArea * twa = addTabWorkArea();
 			GuiWorkArea * wa = twa->addWorkArea(*doc_buffer, *this);
 
-			wa->bufferView().setCursor(bv->cursor());
-			dr.screenUpdate(Update::ForceAll | Update::FitCursor);
+			wa->bufferView().copySettingsFrom(*bv);
+			dr.screenUpdate(Update::ForceAll);
 			setCurrentWorkArea(wa);
 			break;
 		}