Bug [#2288] When window wider than scroll width, compute horizEndPreferred

correctly so that SetScrollInfo is not called nor dwell end notified
unnecessarily.

2 files changed, 9 insertions, 2 deletions

diff --git a/doc/ScintillaHistory.html b/doc/ScintillaHistory.html
index e78ef1070..196a7710d 100644
--- a/doc/ScintillaHistory.html
+++ b/doc/ScintillaHistory.html
@@ -564,6 +564,7 @@
       </tr><tr>
 	<td>Michael Neuroth</td>
 	<td>Arne Scheffler</td>
+	<td>Derek</td>
     </tr>
     </table>
     <h2>Releases</h2>
@@ -580,6 +581,12 @@
 	<li>
 	On GTK, fix potential crash when closing Scintilla instances due to releasing global settings object.
 	</li>
+	<li>
+	On Win32, when window is wider than scroll width,
+	use correct values when checking whether to change horizontal scroll bar so
+	only update and notify dwell end when needed.
+	<a href="https://sourceforge.net/p/scintilla/bugs/2288/">Bug #2288</a>.
+	</li>
     </ul>
     <h3>
        <a href="https://www.scintilla.org/scintilla513.zip">Release 5.1.3</a>
diff --git a/win32/ScintillaWin.cxx b/win32/ScintillaWin.cxx
index a45c7a076..4fd86ec7c 100644
--- a/win32/ScintillaWin.cxx
+++ b/win32/ScintillaWin.cxx
@@ -2340,10 +2340,10 @@ bool ScintillaWin::ModifyScrollBars(Sci::Line nMax, Sci::Line nPage) {
 	}
 
 	const PRectangle rcText = GetTextRectangle();
-	int horizEndPreferred = scrollWidth;
+	int pageWidth = static_cast<int>(rcText.Width());
+	int horizEndPreferred = std::max(scrollWidth, pageWidth-1);
 	if (horizEndPreferred < 0)
 		horizEndPreferred = 0;
-	int pageWidth = static_cast<int>(rcText.Width());
 	if (!horizontalScrollBarVisible || Wrapping())
 		pageWidth = horizEndPreferred + 1;
 	sci.fMask = SIF_PAGE | SIF_RANGE;