4 files changed, 32 insertions, 21 deletions

diff --git a/include/Scintilla.h b/include/Scintilla.h
index fee9f9922..0185d3e5b 100644
--- a/include/Scintilla.h
+++ b/include/Scintilla.h
@@ -334,6 +334,7 @@ typedef sptr_t (*SciFnDirect)(sptr_t ptr, unsigned int iMessage, uptr_t wParam,
 #define SCI_TOGGLEFOLD 2231
 #define SCI_ENSUREVISIBLE 2232
 #define SCI_SETFOLDFLAGS 2233
+#define SCI_ENSUREVISIBLEENFORCEPOLICY 2234
 #define SCI_SETTABINDENTS 2260
 #define SCI_GETTABINDENTS 2261
 #define SCI_SETBACKSPACEUNINDENTS 2262
diff --git a/include/Scintilla.iface b/include/Scintilla.iface
index 2f0baebb6..4bce389e9 100644
--- a/include/Scintilla.iface
+++ b/include/Scintilla.iface
@@ -848,6 +848,10 @@ fun void EnsureVisible=2232(int line,)
 # Set some debugging options for folding
 fun void SetFoldFlags=2233(int flags,)
 
+# Ensure a particular line is visible by expanding any header line hiding it.
+# Use the currently set visibility policy to determine which range to display.
+fun void EnsureVisibleEnforcePolicy=2234(int line,)
+
 # Sets whether a tab pressed when caret is within indentation indents
 set void SetTabIndents=2260(bool tabIndents,)
 
diff --git a/src/Editor.cxx b/src/Editor.cxx
index 1735de498..5b72ac579 100644
--- a/src/Editor.cxx
+++ b/src/Editor.cxx
@@ -3482,12 +3482,12 @@ void Editor::ToggleContraction(int line) {
 
 // Recurse up from this line to find any folds that prevent this line from being visible
 // and unfold them all.
-void Editor::EnsureLineVisible(int lineDoc) {
+void Editor::EnsureLineVisible(int lineDoc, bool enforcePolicy) {
 	if (!cs.GetVisible(lineDoc)) {
 		int lineParent = pdoc->GetFoldParent(lineDoc);
 		if (lineParent >= 0) {
 			if (lineDoc != lineParent)
-				EnsureLineVisible(lineParent);
+				EnsureLineVisible(lineParent, enforcePolicy);
 			if (!cs.GetExpanded(lineParent)) {
 				cs.SetExpanded(lineParent, 1);
 				Expand(lineParent, true);
@@ -3496,23 +3496,25 @@ void Editor::EnsureLineVisible(int lineDoc) {
 		SetScrollBars();
 		Redraw();
 	}
-	int lineDisplay = cs.DisplayFromDoc(lineDoc);
-	if (visiblePolicy & VISIBLE_SLOP) {
-		if ((topLine > lineDisplay) || ((visiblePolicy & VISIBLE_STRICT) && (topLine + visibleSlop > lineDisplay))) {
-			SetTopLine(Platform::Clamp(lineDisplay - visibleSlop, 0, MaxScrollPos()));
-			SetVerticalScrollPos();
-			Redraw();
-		} else if ((lineDisplay > topLine + LinesOnScreen() - 1) ||
-		           ((visiblePolicy & VISIBLE_STRICT) && (lineDisplay > topLine + LinesOnScreen() - 1 - visibleSlop))) {
-			SetTopLine(Platform::Clamp(lineDisplay - LinesOnScreen() + 1 + visibleSlop, 0, MaxScrollPos()));
-			SetVerticalScrollPos();
-			Redraw();
-		}
-	} else {
-		if ((topLine > lineDisplay) || (lineDisplay > topLine + LinesOnScreen() - 1) || (visiblePolicy & VISIBLE_STRICT)) {
-			SetTopLine(Platform::Clamp(lineDisplay - LinesOnScreen() / 2 + 1, 0, MaxScrollPos()));
-			SetVerticalScrollPos();
-			Redraw();
+	if (enforcePolicy) {
+		int lineDisplay = cs.DisplayFromDoc(lineDoc);
+		if (visiblePolicy & VISIBLE_SLOP) {
+			if ((topLine > lineDisplay) || ((visiblePolicy & VISIBLE_STRICT) && (topLine + visibleSlop > lineDisplay))) {
+				SetTopLine(Platform::Clamp(lineDisplay - visibleSlop, 0, MaxScrollPos()));
+				SetVerticalScrollPos();
+				Redraw();
+			} else if ((lineDisplay > topLine + LinesOnScreen() - 1) ||
+					   ((visiblePolicy & VISIBLE_STRICT) && (lineDisplay > topLine + LinesOnScreen() - 1 - visibleSlop))) {
+				SetTopLine(Platform::Clamp(lineDisplay - LinesOnScreen() + 1 + visibleSlop, 0, MaxScrollPos()));
+				SetVerticalScrollPos();
+				Redraw();
+			}
+		} else {
+			if ((topLine > lineDisplay) || (lineDisplay > topLine + LinesOnScreen() - 1) || (visiblePolicy & VISIBLE_STRICT)) {
+				SetTopLine(Platform::Clamp(lineDisplay - LinesOnScreen() / 2 + 1, 0, MaxScrollPos()));
+				SetVerticalScrollPos();
+				Redraw();
+			}
 		}
 	}
 }
@@ -4637,7 +4639,11 @@ sptr_t Editor::WndProc(unsigned int iMessage, uptr_t wParam, sptr_t lParam) {
 		break;
 
 	case SCI_ENSUREVISIBLE:
-		EnsureLineVisible(wParam);
+		EnsureLineVisible(wParam, false);
+		break;
+
+	case SCI_ENSUREVISIBLEENFORCEPOLICY:
+		EnsureLineVisible(wParam, true);
 		break;
 
 	case SCI_SEARCHANCHOR:
diff --git a/src/Editor.h b/src/Editor.h
index 3d7c54e8e..d42f5ad14 100644
--- a/src/Editor.h
+++ b/src/Editor.h
@@ -328,7 +328,7 @@ protected:	// ScintillaBase subclass needs access to much of Editor
 	
 	void Expand(int &line, bool doExpand);
 	void ToggleContraction(int line);
-	void EnsureLineVisible(int lineDoc);
+	void EnsureLineVisible(int lineDoc, bool enforcePolicy);
 	int ReplaceTarget(bool replacePatterns, const char *text, int length=-1);
 
 	virtual sptr_t DefWndProc(unsigned int iMessage, uptr_t wParam, sptr_t lParam) = 0;