OpenOffice Calc Join (Merge, Combine) Multiple Sheets & Files Into One Software

This is a program with a pretty self-explanatory name - it allows you to merge multiple sheets supported by OpenOffice Calc, namely ODS, OTS, SXC and STC.
The interface of the app is based on a standard window where you can import items into the file list by using either the file browser, tree view or 'drag and drop' method.
The file queue provides the source path of each entry. So, all you have to do is select the merging mode (combine all files to one new sheet or workbook), as well as establish the output directory and filename, in order to proceed with the joining procedure.
In addition, you can move items up and down in the list. The program runs on a very low amount of system memory and CPU, so it shouldn't put a strain on the computer. It has a good response time and quickly finishes a task, without causing the operating system to freeze, crash or pop up error dialogs.
On the downside, the software application is quite limited. For example, you cannot preview documents in a built-in frame, make OpenOffice Calc Join (Merge, Combine) Multiple Sheets & Files Into One Software open the output directory or file when the task is done, or minimize the app to the system tray. Plus, the tool has not been updated for a very long time.