Have you ever tried desperately to debug Exceptions in your MPS applications that occur within the Graphical User Interface or within the UI Thread? Unfortunately, these cannot be found in the regular "Event Log" or in the "Messages Tab".
A click on the small Exclamation mark at the bottom right of the application opens a separate Error-Console in which only the fatal IDE-relevant errors can be found:
REM @ECHO OFF
The command line then shows exactly the same exceptions as the "IDE Fatal Errors" console within MPS.
$PATH\jre\bin\java.exe -cp "$CLASSPATH" jetbrains.mps.Launcher