When deleting tab backup file, delete it to recycle bin, for cases where the user did that by accident. Same for snippet file and overwritten export/zip file. See https://www.heidisql.com/forum.php?t=39355

source/apphelpers.pas

@@ -293,6 +293,7 @@ type
   function EncodeURLParam(const Value: String): String;
   procedure StreamWrite(S: TStream; Text: String = '');
   function _GetFileSize(Filename: String): Int64;
+  function DeleteFileWithUndo(sFileName: String): Boolean;
   function MakeInt(Str: String) : Int64;
   function MakeFloat(Str: String): Extended;
   function CleanupNumber(Str: String): String;
@@ -606,6 +607,18 @@ begin
 end;
 
 
+function DeleteFileWithUndo(sFileName: string): Boolean;
+var
+  fos: TSHFileOpStruct;
+begin
+  FillChar(fos, SizeOf(fos), 0);
+  fos.wFunc := FO_DELETE;
+  fos.pFrom := PChar(sFileName);
+  fos.fFlags := FOF_ALLOWUNDO or FOF_NOCONFIRMATION or FOF_SILENT;
+  Result := (0 = ShFileOperation(fos));
+end;
+
+
 {***
   Convert a string-number to an integer-number
 

source/main.pas

@@ -8317,7 +8317,7 @@ begin
   if MessageDialog(_('Delete snippet file?'), snippetfile, mtConfirmation, [mbOk, mbCancel]) = mrOk then
   begin
     Screen.Cursor := crHourGlass;
-    if DeleteFile(snippetfile) then begin
+    if DeleteFileWithUndo(snippetfile) then begin
       // Refresh list with snippets
       SetSnippetFilenames;
     end else begin
@@ -12571,7 +12571,7 @@ begin
     end else begin
       // Delete backup file if tab is closed by user, intentionally
       if (not Tab.MemoBackupFilename.IsEmpty) and FileExists(Tab.MemoBackupFilename) then begin
-        if not DeleteFile(Tab.MemoBackupFilename) then begin
+        if not DeleteFileWithUndo(Tab.MemoBackupFilename) then begin
           ErrorDialog(f_('Backup file could not be deleted: %s', [Tab.MemoBackupFilename]));
         end;
       end;

source/tabletools.pas

@@ -893,7 +893,7 @@ begin
       StartTime := GetTickCount;
       FileNameZip := FExportFileName;
       if FileExists(FileNameZip) then
-        DeleteFile(FileNameZip);
+        DeleteFileWithUndo(FileNameZip);
       Zip := TZipFile.Create;
       Zip.Open(FileNameZip, zmWrite);
       FileNameInZip := ExtractFileName(ChangeFileExt(FileNameZip, '.sql'));