[amibroker] Deleting Format files in Amibroker

[Debdulal Bhattacharyya]

hi all,
I have mistakenly created a format file during importing Intraday data 
using import wizard and there are 10-12 such format files in my 
amibroker which produces some errors if I want to use them during data 
importing.
So I need to delete those format files but I can't as they are still 
in the dropdown list after deleting.
Please help me to solve this problem.
Thanx in advance.