diff --git a/Versions/build.txt b/Versions/build.txt
index f34461850..758f7c981 100644
--- a/Versions/build.txt
+++ b/Versions/build.txt
@@ -1 +1 @@
-1711
+1712
diff --git a/res/Notepad3.exe.manifest.conf b/res/Notepad3.exe.manifest.conf
index 3750c4264..618dbab69 100644
--- a/res/Notepad3.exe.manifest.conf
+++ b/res/Notepad3.exe.manifest.conf
@@ -3,7 +3,7 @@
   <assemblyIdentity
     name="Notepad3"
     processorArchitecture="*"
-    version="5.19.519.1711"
+    version="5.19.519.1712"
     type="win32"
   />
   <description>Notepad3 RC</description>
diff --git a/scintilla/doc/ScintillaHistory.html b/scintilla/doc/ScintillaHistory.html
index cdd31553e..66fcaf36b 100644
--- a/scintilla/doc/ScintillaHistory.html
+++ b/scintilla/doc/ScintillaHistory.html
@@ -568,8 +568,17 @@
 	<a href="https://sourceforge.net/p/scintilla/feature-requests/1280/">Feature #1280</a>.
 	</li>
 	<li>
+	Improved performance of line folding code on large files when no folds are contracted.
+	This improves the time taken to open or close large files.
+	</li>
+	<li>
 	Fix bug where changing identifier sets in lexers preserved previous identifiers.
 	</li>
+	<li>
+	Fixed bug where changing to Unicode would rediscover line end positions even if still
+	sticking to ASCII (not Unicode NEL, LS, PS) line ends.
+	Only noticeable on huge files with over 100,000 lines.
+	</li>
  	<li>
 	Changed behaviour of SCI_STYLESETCASE(*,SC_CASE_CAMEL) so that it only treats 'a-zA-Z'
 	as word characters because this covers the feature's intended use (viewing case-insensitive ASCII-only
diff --git a/scintilla/src/CellBuffer.cxx b/scintilla/src/CellBuffer.cxx
index 4d8e711ee..f2445751f 100644
--- a/scintilla/src/CellBuffer.cxx
+++ b/scintilla/src/CellBuffer.cxx
@@ -678,7 +678,6 @@ void CellBuffer::Allocate(Sci::Position newSize) {
 void CellBuffer::SetUTF8Substance(bool utf8Substance_) {
 	if (utf8Substance != utf8Substance_) {
 		utf8Substance = utf8Substance_;
-		ResetLineEnds();
 	}
 }
 
diff --git a/scintilla/src/ContractionState.cxx b/scintilla/src/ContractionState.cxx
index 565f9e141..8b5821470 100644
--- a/scintilla/src/ContractionState.cxx
+++ b/scintilla/src/ContractionState.cxx
@@ -210,16 +210,24 @@ Sci::Line ContractionState<LINE>::DocFromDisplay(Sci::Line lineDisplay) const {
 
 template <typename LINE>
 void ContractionState<LINE>::InsertLines(Sci::Line lineDoc, Sci::Line lineCount) {
-	for (Sci::Line l = 0; l < lineCount; l++) {
-		InsertLine(lineDoc + l);
+	if (OneToOne()) {
+		linesInDocument += static_cast<LINE>(lineCount);
+	} else {
+		for (Sci::Line l = 0; l < lineCount; l++) {
+			InsertLine(lineDoc + l);
+		}
 	}
 	Check();
 }
 
 template <typename LINE>
 void ContractionState<LINE>::DeleteLines(Sci::Line lineDoc, Sci::Line lineCount) {
-	for (Sci::Line l = 0; l < lineCount; l++) {
-		DeleteLine(lineDoc);
+	if (OneToOne()) {
+		linesInDocument -= static_cast<LINE>(lineCount);
+	} else {
+		for (Sci::Line l = 0; l < lineCount; l++) {
+			DeleteLine(lineDoc);
+		}
 	}
 	Check();
 }
diff --git a/scintilla/src/Editor.cxx b/scintilla/src/Editor.cxx
index 4fb4eb2a5..947b39f6a 100644
--- a/scintilla/src/Editor.cxx
+++ b/scintilla/src/Editor.cxx
@@ -4507,7 +4507,7 @@ void Editor::ButtonDownWithModifiers(Point pt, unsigned int curTime, int modifie
 	if (hoverIndicatorPos != Sci::invalidPosition)
 		if (modifiers & (SCI_ALT | SCI_CTRL)) { DisplayCursor(Window::cursorHand); }
 	// <<<<<<<<<<<<<<<   END NON STD SCI PATCH   <<<<<<<<<<<<<<<
-    //Platform::DebugPrintf("ButtonDown %d %d = %d alt=%d %d\n", curTime, lastClickTime, curTime - lastClickTime, alt, inDragDrop);
+  //Platform::DebugPrintf("ButtonDown %d %d = %d alt=%d %d\n", curTime, lastClickTime, curTime - lastClickTime, alt, inDragDrop);
 	ptMouseLast = pt;
 	const bool ctrl = (modifiers & SCI_CTRL) != 0;
 	const bool shift = (modifiers & SCI_SHIFT) != 0;
diff --git a/scintilla/win32/ScintillaWin.cxx b/scintilla/win32/ScintillaWin.cxx
index 8f3d237aa..32ec95d9f 100644
--- a/scintilla/win32/ScintillaWin.cxx
+++ b/scintilla/win32/ScintillaWin.cxx
@@ -1547,8 +1547,10 @@ sptr_t ScintillaWin::WndProc(unsigned int iMessage, uptr_t wParam, sptr_t lParam
 		break;
 
 		case WM_MOUSEMOVE: {
+// >>>>>>>>>>>>>>>   BEG NON STD SCI PATCH   >>>>>>>>>>>>>>>
 #if 0
 			const Point pt = PointFromLParam(lParam);
+
 			// Windows might send WM_MOUSEMOVE even though the mouse has not been moved:
 			// https://blogs.msdn.com/b/oldnewthing/archive/2003/10/01/55108.aspx
 			XYPOSITION const dx = abs(ptMouseLast.x - pt.x);
@@ -1561,6 +1563,7 @@ sptr_t ScintillaWin::WndProc(unsigned int iMessage, uptr_t wParam, sptr_t lParam
 			const Point pt = PointFromLParam(lParam);
 			SetTrackMouseLeaveEvent(true);
 			ButtonMoveWithModifiers(pt, ::GetMessageTime(), MouseModifiers(wParam));
+// <<<<<<<<<<<<<<<   END NON STD SCI PATCH   <<<<<<<<<<<<<<<
 		}
 		break;
 
@@ -1581,6 +1584,7 @@ sptr_t ScintillaWin::WndProc(unsigned int iMessage, uptr_t wParam, sptr_t lParam
 				CancelModes();
 				SetEmptySelection(PositionFromLocation(PointFromLParam(lParam)));
 			}
+
 			RightButtonDownWithModifiers(pt, ::GetMessageTime(), MouseModifiers(wParam));
 		}
 		break;
diff --git a/src/Edit.c b/src/Edit.c
index ce7c362a1..c17761e59 100644
--- a/src/Edit.c
+++ b/src/Edit.c
@@ -6930,11 +6930,7 @@ void EditHideNotMarkedLineRange(HWND hwnd, bool bHideLines)
     EditFinalizeStyling(hwnd, -1);
     FocusedView.CodeFoldingAvailable = true;
     FocusedView.ShowCodeFolding = true;
-
-    Style_SetFoldingProperties(FocusedView.CodeFoldingAvailable);
-    SciCall_SetProperty("fold.compact", "1");
-    // special case, cause Lexer is mad 
-    SciCall_SetProperty("fold.ahkl.skip", "1");
+    Style_SetFoldingFocusedView();
 
     Style_SetFolding(hwnd, true);
 
diff --git a/src/Styles.c b/src/Styles.c
index 5be9020d3..b93067c15 100644
--- a/src/Styles.c
+++ b/src/Styles.c
@@ -820,6 +820,20 @@ void Style_SetFoldingProperties(bool active)
 }
 
 
+//=============================================================================
+//
+//  Style_SetFoldingFocusedView()
+//
+void Style_SetFoldingFocusedView()
+{
+    SciCall_SetProperty("fold", "1");
+    SciCall_SetProperty("fold.comment", "1");
+    SciCall_SetProperty("fold.compact", "0");
+    SciCall_SetProperty("fold.foldsyntaxbased", "1");
+    SciCall_SetProperty("fold.ahkl.skip", "1");
+}
+
+
 //=============================================================================
 //
 //  Style_SetLexer()
diff --git a/src/Styles.h b/src/Styles.h
index 69d7a006f..22e930216 100644
--- a/src/Styles.h
+++ b/src/Styles.h
@@ -44,6 +44,7 @@ void     Style_DynamicThemesMenuCmd(int cmd, bool bEnableSaveSettings);
 float  Style_GetCurrentFontSize();
 void   Style_SetFoldingAvailability(PEDITLEXER pLexer);
 void   Style_SetFoldingProperties(bool active);
+void   Style_SetFoldingFocusedView();
 void   Style_SetLexer(HWND hwnd,PEDITLEXER pLexNew);
 void   Style_SetUrlHotSpot(HWND hwnd);
 void   Style_SetInvisible(HWND hwnd, bool);
diff --git a/src/VersionEx.h b/src/VersionEx.h
index 98af06d37..b6256335a 100644
--- a/src/VersionEx.h
+++ b/src/VersionEx.h
@@ -8,7 +8,7 @@
 #define VERSION_MAJOR 5
 #define VERSION_MINOR 19
 #define VERSION_REV 519
-#define VERSION_BUILD 1711
+#define VERSION_BUILD 1712
 #define SCINTILLA_VER 415+
 #define ONIGMO_REGEX_VER 6.2.0
 #define VERSION_PATCH RC