Mysterious (?) 'script:...' window appearing after running Fiji macros

Whenever I run a macro (I’m using Fiji) a new window entitled “script: [macro full pathname]” is automatically created. That window is empty, except that it shows the number -17974594 in a ‘Value’ column. This may appear irrelevant, but in fact it is somewhat annoying, as the window cannot be closed by runnig ‘Close All’. So, during a session there is the accumulation of tens and tens of these windows each of which must be closed manually. Somebody knows how to avoid this problem?