Tested in Aqua Data Studio 14.0.0-rc-27 Build #: 34104 on Ubuntu 12.04( Mongo DB 2.4.3)  and Windows XP ( Mongo DB 2.0.9).

1. When insert into the integer type field integer long value e.g. from 2147483648 to 9223372036854775807  - type of the field will change to String. But if then Format it again to the Integer  - type will return back to the integer type. Seems in this case program differs NumberInt(4 byte) and NumberLong(8 bytes). So if field was NumberInt then it does not change automaticaly to NumberLong while edited.

2. Editing of last number symbol of very large long integer values is not possible. For test insert into the integer type e.g. 9223372036854775807 by mean of SQL INSERT statement or by Format String to Integer and try to change last number symbol 7 to 6 and validate. 6 will changes back to 7. Same for smaller number (92233720368547758). Here 8 can't be changed.