Feature [feature-requests:#184]. Add option to disable drag/drop editing

SCI_SETDRAGDROPENABLED. Fully implemented on Win32 but may only prevent dragging
on other platforms.

11 files changed, 60 insertions, 4 deletions

diff --git a/call/ScintillaCall.cxx b/call/ScintillaCall.cxx
index d1d4012b2..093cf9a0d 100644
--- a/call/ScintillaCall.cxx
+++ b/call/ScintillaCall.cxx
@@ -3391,6 +3391,14 @@ Position ScintillaCall::IndexPositionFromLine(Line line, Scintilla::LineCharacte
 	return Call(Message::IndexPositionFromLine, line, static_cast<intptr_t>(lineCharacterIndex));
 }
 
+bool ScintillaCall::DragDropEnabled() {
+	return Call(Message::GetDragDropEnabled);
+}
+
+void ScintillaCall::SetDragDropEnabled(bool dragDropEnabled) {
+	Call(Message::SetDragDropEnabled, dragDropEnabled);
+}
+
 void ScintillaCall::StartRecord() {
 	Call(Message::StartRecord);
 }
diff --git a/doc/ScintillaDoc.html b/doc/ScintillaDoc.html
index 0dfe986f4..d432043f6 100644
--- a/doc/ScintillaDoc.html
+++ b/doc/ScintillaDoc.html
@@ -482,6 +482,8 @@
     *text)</a><br />
      <a class="message" href="#SCI_SETREADONLY">SCI_SETREADONLY(bool readOnly)</a><br />
      <a class="message" href="#SCI_GETREADONLY">SCI_GETREADONLY &rarr; bool</a><br />
+     <a class="message" href="#SCI_GETDRAGDROPENABLED">SCI_GETDRAGDROPENABLED &rarr; bool</a><br />
+     <a class="message" href="#SCI_SETDRAGDROPENABLED">SCI_SETDRAGDROPENABLED(bool dragDropEnabled)</a><br />
      <a class="message" href="#SCI_GETTEXTRANGE">SCI_GETTEXTRANGE(&lt;unused&gt;, Sci_TextRange *tr) &rarr; position</a><br />
      <a class="message" href="#SCI_GETTEXTRANGEFULL">SCI_GETTEXTRANGEFULL(&lt;unused&gt;, Sci_TextRangeFull *tr) &rarr; position</a><br />
      <a class="message" href="#SCI_ALLOCATE">SCI_ALLOCATE(position bytes)</a><br />
@@ -568,6 +570,10 @@
     only, attempts to modify the text cause the <a class="message"
     href="#SCN_MODIFYATTEMPTRO"><code>SCN_MODIFYATTEMPTRO</code></a> notification.</p>
 
+    <p><b id="SCI_GETDRAGDROPENABLED">SCI_GETDRAGDROPENABLED &rarr; bool</b><br />
+     <b id="SCI_SETDRAGDROPENABLED">SCI_SETDRAGDROPENABLED(bool dragDropEnabled)</b><br />
+     These messages get and set the flag controlling whether drag-and-drop is enabled or not.</p>
+
     <p>
     <b id="SCI_GETTEXTRANGE">SCI_GETTEXTRANGE(&lt;unused&gt;, <a class="jump" href="#Sci_TextRange">Sci_TextRange</a> *tr) &rarr; position</b><br />
     <b id="SCI_GETTEXTRANGEFULL">SCI_GETTEXTRANGEFULL(&lt;unused&gt;, <a class="jump" href="#Sci_TextRangeFull">Sci_TextRangeFull</a> *tr) &rarr; position</b><br />
diff --git a/doc/ScintillaHistory.html b/doc/ScintillaHistory.html
index 12b233b4f..1148abaa1 100644
--- a/doc/ScintillaHistory.html
+++ b/doc/ScintillaHistory.html
@@ -592,6 +592,7 @@
 	<td>Ahmet Sait</td>
 	<td>Sven Ritter</td>
 	<td>Stefan Löffler</td>
+	<td>Nathaniel Braun</td>
     </tr>
     </table>
     <h2 id="Releases">Releases</h2>
@@ -603,6 +604,10 @@
 	Released 10 November 2025.
 	</li>
 	<li>
+	Add option to disable drag/drop editing.
+	<a href="https://sourceforge.net/p/scintilla/feature-requests/184/">Feature #184</a>.
+	</li>
+	<li>
 	Fix SCI_SETSELECTIONNSTART and SCI_SETSELECTIONNEND to behave more sensibly.
 	<a href="https://sourceforge.net/p/scintilla/bugs/2488/">Bug #2488</a>.
 	</li>
diff --git a/include/Scintilla.h b/include/Scintilla.h
index f7afa4f50..b6786097e 100644
--- a/include/Scintilla.h
+++ b/include/Scintilla.h
@@ -1194,6 +1194,8 @@ typedef sptr_t (*SciFnDirectStatus)(sptr_t ptr, unsigned int iMessage, uptr_t wP
 #define SCI_RELEASELINECHARACTERINDEX 2712
 #define SCI_LINEFROMINDEXPOSITION 2713
 #define SCI_INDEXPOSITIONFROMLINE 2714
+#define SCI_GETDRAGDROPENABLED 2818
+#define SCI_SETDRAGDROPENABLED 2819
 #define SCI_STARTRECORD 3001
 #define SCI_STOPRECORD 3002
 #define SCI_GETLEXER 4002
diff --git a/include/Scintilla.iface b/include/Scintilla.iface
index 9ba834aed..6262f7c1b 100644
--- a/include/Scintilla.iface
+++ b/include/Scintilla.iface
@@ -3258,6 +3258,12 @@ fun line LineFromIndexPosition=2713(position pos, LineCharacterIndexType lineCha
 # Retrieve the position measured in index units at the start of a document line.
 fun position IndexPositionFromLine=2714(line line, LineCharacterIndexType lineCharacterIndex)
 
+# Get whether drag-and-drop is enabled or disabled
+get bool GetDragDropEnabled=2818(,)
+
+# Enable or disable drag-and-drop
+set void SetDragDropEnabled=2819(bool dragDropEnabled,)
+
 # Start notifying the container of all key presses and commands.
 fun void StartRecord=3001(,)
 
diff --git a/include/ScintillaCall.h b/include/ScintillaCall.h
index 7a98c7e3d..2c065c03f 100644
--- a/include/ScintillaCall.h
+++ b/include/ScintillaCall.h
@@ -893,6 +893,8 @@ public:
 	void ReleaseLineCharacterIndex(Scintilla::LineCharacterIndexType lineCharacterIndex);
 	Line LineFromIndexPosition(Position pos, Scintilla::LineCharacterIndexType lineCharacterIndex);
 	Position IndexPositionFromLine(Line line, Scintilla::LineCharacterIndexType lineCharacterIndex);
+	bool DragDropEnabled();
+	void SetDragDropEnabled(bool dragDropEnabled);
 	void StartRecord();
 	void StopRecord();
 	int Lexer();
diff --git a/include/ScintillaMessages.h b/include/ScintillaMessages.h
index 6a33f5c6d..d327bf7c1 100644
--- a/include/ScintillaMessages.h
+++ b/include/ScintillaMessages.h
@@ -799,6 +799,8 @@ enum class Message {
 	ReleaseLineCharacterIndex = 2712,
 	LineFromIndexPosition = 2713,
 	IndexPositionFromLine = 2714,
+	GetDragDropEnabled = 2818,
+	SetDragDropEnabled = 2819,
 	StartRecord = 3001,
 	StopRecord = 3002,
 	GetLexer = 4002,
diff --git a/src/Editor.cxx b/src/Editor.cxx
index 1ad99c3ca..a2c3e0fe9 100644
--- a/src/Editor.cxx
+++ b/src/Editor.cxx
@@ -143,6 +143,7 @@ Editor::Editor() : durationWrapOneByte(0.000001, 0.00000001, 0.00001) {
 	dwelling = false;
 	ptMouseLast.x = 0;
 	ptMouseLast.y = 0;
+	dragDropEnabled = true;
 	inDragDrop = DragDrop::none;
 	dropWentOutside = false;
 	posDrop = SelectionPosition(Sci::invalidPosition);
@@ -5041,7 +5042,7 @@ void Editor::ButtonMoveWithModifiers(Point pt, unsigned int, KeyMod modifiers) {
 		AllowVirtualSpace(virtualSpaceOptions, sel.IsRectangular()));
 	movePos = MovePositionOutsideChar(movePos, sel.MainCaret() - movePos.Position());
 
-	if (inDragDrop == DragDrop::initial) {
+	if (dragDropEnabled && inDragDrop == DragDrop::initial) {
 		if (DragThreshold(ptMouseLast, pt)) {
 			ChangeMouseCapture(false);
 			SetDragPosition(movePos);
@@ -5139,7 +5140,7 @@ void Editor::ButtonMoveWithModifiers(Point pt, unsigned int, KeyMod modifiers) {
 			}
 		}
 		// Display regular (drag) cursor over selection
-		if (PointInSelection(pt) && !SelectionEmpty()) {
+		if (PointInSelection(pt) && !SelectionEmpty() && dragDropEnabled) {
 			DisplayCursor(Window::Cursor::arrow);
 			SetHoverIndicatorPosition(Sci::invalidPosition);
 		} else {
@@ -7084,6 +7085,13 @@ sptr_t Editor::WndProc(Message iMessage, uptr_t wParam, sptr_t lParam) {
 	case Message::GetBufferedDraw:
 		return view.bufferedDraw;
 
+	case Message::GetDragDropEnabled:
+		return dragDropEnabled;
+
+	case Message::SetDragDropEnabled:
+		dragDropEnabled = wParam != 0;
+		break;
+
 #ifdef INCLUDE_DEPRECATED_FEATURES
 	case SCI_GETTWOPHASEDRAW:
 		return view.phasesDraw == EditView::phasesTwo;
diff --git a/src/Editor.h b/src/Editor.h
index f8bc18970..95b83f1f7 100644
--- a/src/Editor.h
+++ b/src/Editor.h
@@ -238,6 +238,7 @@ protected:	// ScintillaBase subclass needs access to much of Editor
 	bool dwelling;
 	enum class TextUnit { character, word, subLine, wholeLine } selectionUnit;
 	Point ptMouseLast;
+	bool dragDropEnabled;
 	enum class DragDrop { none, initial, dragging } inDragDrop;
 	bool dropWentOutside;
 	SelectionPosition posDrop;
diff --git a/test/simpleTests.py b/test/simpleTests.py
index 4e6a51d59..0a14a4bdb 100644
--- a/test/simpleTests.py
+++ b/test/simpleTests.py
@@ -260,6 +260,13 @@ class TestSimple(unittest.TestCase):
 		self.assertEqual(self.ed.CanUndo(), 0)
 		self.ed.UndoCollection = 1
 
+	def testDragDrop(self):
+		self.assertEqual(self.ed.DragDropEnabled, 1)
+		self.ed.DragDropEnabled = 0
+		self.assertEqual(self.ed.DragDropEnabled, 0)
+		self.ed.DragDropEnabled = 1
+		self.assertEqual(self.ed.DragDropEnabled, 1)
+
 	def testGetColumn(self):
 		self.ed.AddText(1, b"x")
 		self.assertEqual(self.ed.GetColumn(0), 0)
diff --git a/win32/ScintillaWin.cxx b/win32/ScintillaWin.cxx
index dfe075293..17f686c21 100644
--- a/win32/ScintillaWin.cxx
+++ b/win32/ScintillaWin.cxx
@@ -1754,7 +1754,7 @@ Window::Cursor ScintillaWin::ContextCursor(Point pt) {
 	// Display regular (drag) cursor over selection
 	if (PointInSelMargin(pt)) {
 		return GetMarginCursor(pt);
-	} else if (!SelectionEmpty() && PointInSelection(pt)) {
+	} else if (!SelectionEmpty() && PointInSelection(pt) && dragDropEnabled) {
 		return Window::Cursor::arrow;
 	} else if (PointIsHotspot(pt)) {
 		return Window::Cursor::hand;
@@ -3721,6 +3721,10 @@ STDMETHODIMP_(ULONG) ScintillaWin::Release() {
 /// Implement IDropTarget
 STDMETHODIMP ScintillaWin::DragEnter(LPDATAOBJECT pIDataSource, DWORD grfKeyState,
                                      POINTL, PDWORD pdwEffect) {
+	if (!dragDropEnabled) {
+		*pdwEffect = DROPEFFECT_NONE;
+		return S_OK;
+	}
 	if (!pIDataSource )
 		return E_POINTER;
 	FORMATETC fmtu = {CF_UNICODETEXT, nullptr, DVASPECT_CONTENT, -1, TYMED_HGLOBAL };
@@ -3737,7 +3741,7 @@ STDMETHODIMP ScintillaWin::DragEnter(LPDATAOBJECT pIDataSource, DWORD grfKeyStat
 
 STDMETHODIMP ScintillaWin::DragOver(DWORD grfKeyState, POINTL pt, PDWORD pdwEffect) {
 	try {
-		if (!hasOKText || pdoc->IsReadOnly()) {
+		if (!dragDropEnabled || !hasOKText || pdoc->IsReadOnly()) {
 			*pdwEffect = DROPEFFECT_NONE;
 			return S_OK;
 		}
@@ -3771,6 +3775,11 @@ STDMETHODIMP ScintillaWin::Drop(LPDATAOBJECT pIDataSource, DWORD grfKeyState,
 	try {
 		*pdwEffect = EffectFromState(grfKeyState);
 
+		if (!dragDropEnabled) {
+			*pdwEffect = DROPEFFECT_NONE;
+			return S_OK;
+		}
+
 		if (!pIDataSource)
 			return E_POINTER;