blankFill resource

From The x3270 Wiki
Type Default Option
Boolean true

This resource has effect only in 3270 mode.

When blankFill is true, the emulator will automatically convert trailing blanks in a field to NULs in order to insert a character, and when a character is typed into the middle of a field, it will automatically convert leading NULs to blanks so that input data is not squeezed to the left. This works around some of the quirkier behaviors of real 3270 terminals.