Applying a split to the JSL editor window causes the dirty flag to be set (i.e.the save icon becomes enabled).
Please don't do this! Reserve the dirty flag to code changes only.
Use - Case:
Seeing the save icon appear on an code that I am reviewing causes me to immediately close the window in case I have accidentally interfered with the code - you know the type of thing, where you have typed 'c' into the code when you meant to do CTRL-C).