From 1f48115666d7873d7f0b0e96a1d807b0542c790c Mon Sep 17 00:00:00 2001
From: Don Ho <don.h@free.fr>
Date: Wed, 28 May 2025 15:34:20 +0200
Subject: [PATCH] Fix regression of folding state not being remembered through
 sessions

The regression is introduced by:
https://github.com/notepad-plus-plus/notepad-plus-plus/commit/83755ca15584bddf8e83cffcc8a5c71ce1f594e2#diff-d88ddee57a027ab23daf332c4778ced0cee352edcb34efdda1b218e8a75c61b2L2636

The culprit of this regression is the deletion of following 4 lines in the commit above:
```
void ScintillaEditView::fold(size_t line, bool mode, bool shouldBeNotified/* = true*/)
{
	auto endStyled = execute(SCI_GETENDSTYLED);
	auto len = execute(SCI_GETTEXTLENGTH);

	if (endStyled < len)
		execute(SCI_COLOURISE, 0, -1);
```
The method "ScintillaEditView::fold()" is called not only on manual folding by the users, but also on:

1. startup's loading session to restore the folding state programmatically.
2. after startup, switching among the documents to restore the folding state programmatically.

The above lines are important for the case 1.

However, these lines are necessary only on the first load of each file after the startup of Notepad++.
"execute(SCI_COLOURISE, 0, -1);" needs to be run for once (the case 1), not twice or more (the case 2).

So if there's a way to detect if a document has been run "execute(SCI_COLOURISE, 0, -1);" once (in the case 1),
and don't run it again (the case 2), it will save the time to switch among the document.

Fix #16597, close #16599
---
 PowerEditor/src/NppIO.cpp                     |  1 +
 .../ScintillaComponent/ScintillaEditView.cpp  | 21 +++++++++++++++++++
 2 files changed, 22 insertions(+)

diff --git a/PowerEditor/src/NppIO.cpp b/PowerEditor/src/NppIO.cpp
index de426304d..bcc7fce0e 100644
--- a/PowerEditor/src/NppIO.cpp
+++ b/PowerEditor/src/NppIO.cpp
@@ -2521,6 +2521,7 @@ bool Notepad_plus::loadSession(Session & session, bool isSnapshotMode, const wch
 			allSessionFilesLoaded = false;
 		}
 	}
+
 	if (mainIndex2Update != -1)
 	{
 		_isFolding = true;
diff --git a/PowerEditor/src/ScintillaComponent/ScintillaEditView.cpp b/PowerEditor/src/ScintillaComponent/ScintillaEditView.cpp
index d1584c5bf..02032503a 100644
--- a/PowerEditor/src/ScintillaComponent/ScintillaEditView.cpp
+++ b/PowerEditor/src/ScintillaComponent/ScintillaEditView.cpp
@@ -2592,6 +2592,27 @@ bool ScintillaEditView::isCurrentLineFolded() const
 
 void ScintillaEditView::fold(size_t line, bool mode, bool shouldBeNotified/* = true*/)
 {
+	auto endStyled = execute(SCI_GETENDSTYLED);
+	auto len = execute(SCI_GETTEXTLENGTH);
+
+	if (endStyled < len)
+		execute(SCI_COLOURISE, 0, -1);
+/*
+The method ScintillaEditView::fold() is called not only on manual folding by the users, but also on:
+
+1. startup's loading session to restore the folding state programmatically.
+2. after startup, switching among the documents to restore the folding state programmatically.
+
+The above lines are important for the case 1.
+
+However, these lines are necessary only on the first load of each file after the startup of Notepad++.
+"execute(SCI_COLOURISE, 0, -1);" needs to be run for once (the case 1), not twice or more (the case 2).
+
+So if there's a way to detect if a document has been run "execute(SCI_COLOURISE, 0, -1);" once (in the case 1),
+and don't run it again (the case 2), it will save the time to switch among the document.
+*/
+
+
 	intptr_t headerLine;
 	auto level = execute(SCI_GETFOLDLEVEL, line);