Here you can define the behaviour of SrcEdit when you enter a tab character.

Select "Tab Size" to use actual tabs.
When you enter the tab character, a '\t' will be stored in the file. All tabs already in the file will be displayed as a blank space that is the amount of pixels wide as the field there says.

Select "Spaces" to replace spaces for tabs.
Entering a tab character will not insert '\t' but rather however many spaces are set here. This way you may enjoy the speed of using the tab key even if you prefer spaces.

The auto indent will indent the "next" line by copying any tabs/spaces characters preseeding the entered text of the origin line.
