diff --git a/source/lazaruscompat.pas b/source/lazaruscompat.pas
index 39a8a504..ac1c2338 100644
--- a/source/lazaruscompat.pas
+++ b/source/lazaruscompat.pas
@@ -37,6 +37,7 @@ type
   TStringsHelper = class helper for TStrings
     public
       function Contains(const S: String): Boolean;
+      function IsEmpty: Boolean;
   end;
 
 const
@@ -251,5 +252,10 @@ begin
   Result := IndexOf(S) >= 0;
 end;
 
+function TStringsHelper.IsEmpty: Boolean;
+begin
+  Result := Count = 0;
+end;
+
 end.
 
diff --git a/source/main.pas b/source/main.pas
index 515b61b3..62eb79a6 100644
--- a/source/main.pas
+++ b/source/main.pas
@@ -1324,6 +1324,7 @@ type
     procedure SetSnippetFilenames;
     function TreeClickHistoryPrevious(MayBeNil: Boolean=False): PVirtualNode;
     procedure OperationRunning(Runs: Boolean);
+    procedure OpenQueryFiles(Filenames: TStrings; Encoding: TEncoding; ForceRun: Boolean);
     function RunQueryFiles(Filenames: TStrings; Encoding: TEncoding; ForceRun: Boolean): Boolean;
     function RunQueryFile(Filename: String; Encoding: TEncoding; Conn: TDBConnection;
       FilesizeSum: Int64; var CurrentPosition: Int64): Boolean;
@@ -2143,7 +2144,6 @@ var
   StatsCall: THttpDownload;
   StatsURL: String;
   SessionPaths: TStringlist;
-  Tab: TQueryTab;
 begin
   // Check for connection parameters on commandline or show connections form.
   if AppSettings.ReadBool(asUpdatecheck) then begin
@@ -2259,14 +2259,7 @@ begin
   end;
 
   // Load SQL file(s) by command line
-  if not RunQueryFiles(FileNames, nil, false) then begin
-    for i:=0 to FileNames.Count-1 do begin
-      Tab := GetOrCreateEmptyQueryTab(False);
-      Tab.LoadContents(FileNames[i], True, nil);
-      if i = FileNames.Count-1 then
-        SetMainTab(Tab.TabSheet);
-    end;
-  end;
+  OpenQueryFiles(FileNames, nil, False);
 
   MainFormAfterCreateDone := True;
 end;
@@ -3936,10 +3929,9 @@ end;
 // Load SQL-file, make sure that SheetQuery is activated
 procedure TMainForm.actLoadSQLExecute(Sender: TObject);
 var
-  i, ProceedResult: Integer;
+  ProceedResult: Integer;
   Dialog: TExtFileOpenDialog;
   Encoding: TEncoding;
-  Tab: TQueryTab;
 begin
   AppSettings.ResetPath;
   Dialog := TExtFileOpenDialog.Create(Self);
@@ -3961,14 +3953,7 @@ begin
     end;
 
     if ProceedResult = mrYes then begin
-      if not RunQueryFiles(Dialog.Files, Encoding, Sender=actRunSQL) then begin
-        for i:=0 to Dialog.Files.Count-1 do begin
-          Tab := GetOrCreateEmptyQueryTab(False);
-          Tab.LoadContents(Dialog.Files[i], True, Encoding);
-          if i = Dialog.Files.Count-1 then
-            SetMainTab(Tab.TabSheet);
-        end;
-      end;
+      OpenQueryFiles(Dialog.Files, Encoding, Sender=actRunSQL);
     end;
     AppSettings.WriteInt(asFileDialogEncoding, Dialog.EncodingIndex, Self.Name);
   end;
@@ -3976,6 +3961,51 @@ begin
 end;
 
 
+procedure TMainForm.OpenQueryFiles(Filenames: TStrings; Encoding: TEncoding; ForceRun: Boolean);
+var
+  Tab, FileInTab: TQueryTab;
+  FileHints: TStringList;
+  i: Integer;
+begin
+  // Decides whether to run or load files, prevents duplicates etc.
+  if RunQueryFiles(Filenames, Encoding, ForceRun) then
+    Exit;
+
+  FileHints := TStringList.Create;
+
+  for i:=0 to Filenames.Count-1 do begin
+
+    FileInTab := nil;
+    for Tab in QueryTabs do begin
+      if Tab.MemoFilename = Filenames[i] then begin
+        FileInTab := Tab;
+        FileHints.Add(f_('This file is already open in query tab #%d.', [FileInTab.Number]) + ' ' + ExtractFileName(Filenames[i]));
+        if i = Filenames.Count-1 then
+          SetMainTab(FileInTab.TabSheet);
+        Break;
+      end;
+    end;
+
+    if not Assigned(FileInTab) then begin
+      Tab := GetOrCreateEmptyQueryTab(False);
+      Tab.LoadContents(Filenames[i], True, Encoding);
+      if i = Filenames.Count-1 then
+        SetMainTab(Tab.TabSheet);
+    end;
+  end;
+
+  if not FileHints.IsEmpty then begin
+    if MainFormAfterCreateDone then
+      MessageDialog(FileHints.Text, mtInformation, [mbOK])
+    else begin
+      for i:=0 to FileHints.Count-1 do
+        LogSQL(FileHints[i]);
+    end;
+  end;
+  FileHints.Free;
+end;
+
+
 function TMainForm.RunQueryFiles(Filenames: TStrings; Encoding: TEncoding; ForceRun: Boolean): Boolean;
 var
   i, FilesProcessed: Integer;
@@ -5189,7 +5219,6 @@ var
   Filename: String;
   FileList: TStringList;
   p: Integer;
-  Tab: TQueryTab;
 begin
   // Click on the popupQueryLoad
   Filename := (Sender as TMenuItem).Caption;
@@ -5202,10 +5231,7 @@ begin
   end;
   FileList := TStringList.Create;
   FileList.Add(Filename);
-  if not RunQueryFiles(FileList, nil, false) then begin
-    Tab := GetOrCreateEmptyQueryTab(True);
-    Tab.LoadContents(Filename, True, nil);
-  end;
+  OpenQueryFiles(FileList, nil, False);
   FileList.Free;
 end;
 
@@ -7769,12 +7795,7 @@ begin
   // query-memo - load their contents into seperate tabs
   Files := TStringList.Create;
   Files.AddStrings(FileNames);
-  if not RunQueryFiles(Files, nil, False) then begin
-    for i:=0 to Files.Count-1 do begin
-      Tab := GetOrCreateEmptyQueryTab(True);
-      Tab.LoadContents(Files[i], False, nil);
-    end;
-  end;
+  OpenQueryFiles(Files, nil, False);
   Files.Free;
 end;
 
@@ -13637,12 +13658,7 @@ begin
     LogSQL(f_('Preventing second application instance - disabled in %s > %s > %s.', [_('Tools'), _('Preferences'), _('General')]), lcInfo);
     ConnectionParams := nil;
     ParseCommandLine(ParamBlobToStr(Msg.CopyDataStruct.lpData), ConnectionParams, FileNames, RunFrom);
-    if not RunQueryFiles(FileNames, nil, False) then begin
-      for i:=0 to FileNames.Count-1 do begin
-        Tab := GetOrCreateEmptyQueryTab(True);
-        Tab.LoadContents(FileNames[i], True, nil);
-      end;
-    end;
+    OpenQueryFiles(FileNames, nil, False);
     if ConnectionParams <> nil then
       InitConnection(ConnectionParams, True, Connection);
   end else