Menu: File -> Append Log
Accelerator: Ctrl + M
Toolbar: 
Appends the next available logfile of the current logfile sequence, loading it and appending its logmessages to the existing logmessages in the current logfile document window. A counter (+1, +2 ... +n) after the title bar appears in the window’s title. It shows how many logfiles of the logfile sequence you have loaded in addition to the first logfile.
If a filter is active, only the logmessages passing this filter are shown.
Note:
Invoking this function again has no effect until the end of the loading process.