From 0f7ec0d6fed6eecd58847e7e4a2b260e6a7431ad Mon Sep 17 00:00:00 2001
From: Alexey Yakovlev <yallie@users.noreply.github.com>
Date: Sun, 11 Mar 2012 00:50:47 +0400
Subject: [PATCH] Improved LoadSourceFile() method: added cleaning undo buffer
 and resetting visible range.

---
 .../Highlighter/FastColoredTextBoxHighlighter.cs    |  3 +--
 Irony.GrammarExplorer/fmGrammarExplorer.cs          | 13 +++++++++++--
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/Irony.GrammarExplorer/Highlighter/FastColoredTextBoxHighlighter.cs b/Irony.GrammarExplorer/Highlighter/FastColoredTextBoxHighlighter.cs
index 0d9fcb7..406721b 100644
--- a/Irony.GrammarExplorer/Highlighter/FastColoredTextBoxHighlighter.cs
+++ b/Irony.GrammarExplorer/Highlighter/FastColoredTextBoxHighlighter.cs
@@ -217,7 +217,7 @@ public void LockTextBox() {
       //SendMessage(TextBox.Handle, WM_SETREDRAW, 0, IntPtr.Zero);
       // Stop sending of events:
       _savedEventMask = SendMessage(TextBox.Handle, EM_GETEVENTMASK, 0, IntPtr.Zero);
-      //SendMessage(TextBox.Handle, EM_SETEVENTMASK, 0, IntPtr.Zero);
+      SendMessage(TextBox.Handle, EM_SETEVENTMASK, 0, IntPtr.Zero);
     }
 
     public void UnlockTextBox() {
@@ -239,7 +239,6 @@ void Adapter_ColorizeTokens(object sender, ColorizeEventArgs args) {
           var tokenRange = TextBox.GetRange(tkn.Location.Position, tkn.Location.Position + tkn.Length);
           var tokenStyle = GetTokenStyle(tkn);
           tokenRange.SetStyle(tokenStyle);
-
         }
       } finally {
         TextBox.EndUpdate();
diff --git a/Irony.GrammarExplorer/fmGrammarExplorer.cs b/Irony.GrammarExplorer/fmGrammarExplorer.cs
index 2488c12..e3f86cd 100644
--- a/Irony.GrammarExplorer/fmGrammarExplorer.cs
+++ b/Irony.GrammarExplorer/fmGrammarExplorer.cs
@@ -405,9 +405,11 @@ private void LoadSourceFile(string path) {
       try {
         reader = new StreamReader(path);
         txtSource.Text = null;  //to clear any old formatting
+        txtSource.ClearUndo();
+        txtSource.ClearStylesBuffer();
         txtSource.Text = reader.ReadToEnd();
-        txtSource.SelectionStart = 0;
-        txtSource.SelectionLength = 0;
+        txtSource.SetVisibleState(0, FastColoredTextBoxNS.VisibleState.Visible);
+        txtSource.Selection = txtSource.GetRange(0, 0);
       } catch (Exception e) {
         MessageBox.Show(e.Message);
       } finally {
@@ -433,9 +435,16 @@ private void StopHighlighter() {
       ClearHighlighting();
     }
     private void ClearHighlighting() {
+      var selectedRange = txtSource.Selection;
+      var visibleRange = txtSource.VisibleRange;
+      var firstVisibleLine = Math.Min(visibleRange.Start.iLine, visibleRange.End.iLine);
+
       var txt = txtSource.Text;
       txtSource.Clear();
       txtSource.Text = txt; //remove all old highlighting
+
+      txtSource.SetVisibleState(firstVisibleLine, FastColoredTextBoxNS.VisibleState.Visible);
+      txtSource.Selection = selectedRange;
     }
     private void EnableHighlighter(bool enable) {
       if (_highlighter != null)