[Koha] Problem with browser

[Davide Spanu]

Good morning,
I have a problem with my koha server. I realized that after importing a record (so before entering the copy data) the window of some browsers closes automatically (Chrome and Firefox). Before this problem did not occur (and I did not change any settings in either Koha or the server). Can you tell me what it can depend on?
Thank you so much.
Davide