diff --git a/components/synedit/lazsynedittext.pas b/components/synedit/lazsynedittext.pas
index a573e49290..22efafa04c 100644
--- a/components/synedit/lazsynedittext.pas
+++ b/components/synedit/lazsynedittext.pas
@@ -283,7 +283,7 @@ type
    procedure FlushNotificationCache; virtual; abstract;
   public
     // Char bounds // 1 based (1 is the 1st char in the line)
-    function LogicPosAddChars(const ALine: String; ALogicalPos, ACount: integer): Integer; virtual; abstract;
+    function LogicPosAddChars(const ALine: String; ALogicalPos, ACount: integer; AllowPastEOL: Boolean = False): Integer; virtual; abstract;
     function LogicPosIsAtChar(const ALine: String; ALogicalPos: integer): Boolean; virtual; abstract;
     function LogicPosAdjustToChar(const ALine: String; ALogicalPos: integer;
                                   ANext: Boolean = False): Integer; virtual; abstract;
@@ -405,7 +405,7 @@ type
     property NextLines: TSynEditStrings read fSynStrings write SetSynStrings;
   public
     // Char bounds // 1 based (1 is the 1st char in the line)
-    function LogicPosAddChars(const ALine: String; ALogicalPos, ACount: integer): Integer; override;
+    function LogicPosAddChars(const ALine: String; ALogicalPos, ACount: integer; AllowPastEOL: Boolean = False): Integer; override;
     function LogicPosIsAtChar(const ALine: String; ALogicalPos: integer): Boolean; override;
     function LogicPosAdjustToChar(const ALine: String; ALogicalPos: integer;
                                   ANext: Boolean = False): Integer; override;
@@ -1281,8 +1281,8 @@ begin
   fSynStrings.FlushNotificationCache;
 end;
 
-function TSynEditStringsLinked.LogicPosAddChars(const ALine: String; ALogicalPos,
-  ACount: integer): Integer;
+function TSynEditStringsLinked.LogicPosAddChars(const ALine: String;
+  ALogicalPos, ACount: integer; AllowPastEOL: Boolean): Integer;
 begin
   Result := fSynStrings.LogicPosAddChars(ALine, ALogicalPos, ACount);
 end;
diff --git a/components/synedit/synedit.pp b/components/synedit/synedit.pp
index 27fc786942..717f53389b 100644
--- a/components/synedit/synedit.pp
+++ b/components/synedit/synedit.pp
@@ -2497,7 +2497,7 @@ end;
 
 function TCustomSynEdit.GetCharLen(const Line: string; CharStartPos: integer): integer;
 begin
-  Result := FLines.LogicPosAddChars(Line, CharStartPos, 1) - CharStartPos;
+  Result := FLines.LogicPosAddChars(Line, CharStartPos, 1, True) - CharStartPos;
 end;
 
 function TCustomSynEdit.GetLogicalCaretXY: TPoint;
diff --git a/components/synedit/synedittextbuffer.pp b/components/synedit/synedittextbuffer.pp
index 8a0352986a..38d9c30755 100644
--- a/components/synedit/synedittextbuffer.pp
+++ b/components/synedit/synedittextbuffer.pp
@@ -235,7 +235,7 @@ type
     property Modified: Boolean read FModified write SetModified;
   public
     // Char bounds // 1 based (1 is the 1st char in the line)
-    function LogicPosAddChars(const ALine: String; ALogicalPos, ACount: integer): Integer; override;
+    function LogicPosAddChars(const ALine: String; ALogicalPos, ACount: integer; AllowPastEOL: Boolean = False): Integer; override;
     function LogicPosIsAtChar(const ALine: String; ALogicalPos: integer): Boolean; override;
     function LogicPosAdjustToChar(const ALine: String; ALogicalPos: integer;
                                   ANext: Boolean = False): Integer; override;
@@ -1056,7 +1056,7 @@ begin
 end;
 
 function TSynEditStringList.LogicPosAddChars(const ALine: String; ALogicalPos,
-  ACount: integer): Integer;
+  ACount: integer; AllowPastEOL: Boolean): Integer;
 begin
   // UTF8 handing of chars
   Result := ALogicalPos;
@@ -1070,10 +1070,14 @@ begin
       if (ALine[Result] in [#0..#127, #192..#255]) and (not LogicPosIsCombining(ALine, Result)) then
         dec(ACount);
     end;
-    while (Result > 1) and
-          ( (not(ALine[Result] in [#0..#127, #192..#255])) or LogicPosIsCombining(ALine, Result) )
-    do
-      dec(Result);
+    if AllowPastEOL then
+      Result := Result + ACount;
+
+    if (Result <= length(ALine)) then
+      while (Result > 1) and
+            ( (not(ALine[Result] in [#0..#127, #192..#255])) or LogicPosIsCombining(ALine, Result) )
+      do
+        dec(Result);
   end else begin
     while (Result > 1) and (ACount < 0) do begin
       dec(Result);