From 8c750cef9cdad542f1539e67bf69ec3f263e3e0f Mon Sep 17 00:00:00 2001
From: whitequark <whitequark@whitequark.org>
Date: Sat, 23 Nov 2019 15:06:36 +0000
Subject: [PATCH] Freeze the scrollbar while editor is open in property
 browser.

Before this commit, the scrollbar would move freely, without changing
the position of the viewport. It would be reset after editing is
finished.
---
 src/platform/guimac.mm  | 5 +++--
 src/platform/guiwin.cpp | 6 +++++-
 src/textwin.cpp         | 4 +++-
 3 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/src/platform/guimac.mm b/src/platform/guimac.mm
index ad4871a4..33901ff6 100644
--- a/src/platform/guimac.mm
+++ b/src/platform/guimac.mm
@@ -952,9 +952,10 @@ public:
     }
 
     void SetScrollbarPosition(double pos) override {
-        if(pos > ssView.scrollerMax) {
+        if(pos > ssView.scrollerMax)
             pos = ssView.scrollerMax;
-        }
+        if(GetScrollbarPosition() == pos)
+            return;
         [nsScroller setDoubleValue:(pos / (ssView.scrollerMax - ssView.scrollerMin))];
         if(onScrollbarAdjusted) {
             onScrollbarAdjusted(pos);
diff --git a/src/platform/guiwin.cpp b/src/platform/guiwin.cpp
index b2ae8105..bd1b42e7 100644
--- a/src/platform/guiwin.cpp
+++ b/src/platform/guiwin.cpp
@@ -1354,7 +1354,11 @@ public:
         SCROLLINFO si = {};
         si.cbSize = sizeof(si);
         si.fMask  = SIF_POS;
-        si.nPos   = (UINT)(pos * SCROLLBAR_UNIT);
+        sscheck(GetScrollInfo(hWindow, SB_VERT, &si));
+        if(si.nPos == (int)(pos * SCROLLBAR_UNIT))
+            return;
+
+        si.nPos   = (int)(pos * SCROLLBAR_UNIT);
         sscheck(SetScrollInfo(hWindow, SB_VERT, &si, /*redraw=*/TRUE));
 
         // Windows won't synthesize a WM_VSCROLL for us here.
diff --git a/src/textwin.cpp b/src/textwin.cpp
index 11d30484..131e12e9 100644
--- a/src/textwin.cpp
+++ b/src/textwin.cpp
@@ -1129,8 +1129,10 @@ void TextWindow::MouseLeave() {
 }
 
 void TextWindow::ScrollbarEvent(double newPos) {
-    if(window->IsEditorVisible())
+    if(window->IsEditorVisible()) {
+        window->SetScrollbarPosition(scrollPos);
         return;
+    }
 
     int bottom = top[rows-1] + 2;
     newPos = min((int)newPos, bottom - halfRows);