The Tabs tab has these components:
Indent size Lets you set the size of indents (in number of spaces).
Insert spaces Inserts n spaces when you press the Tab key instead of inserting one tab character. The value for n will be between one and the number of indent size spaces, depending on how many spaces are required to move the cursor forward to the next tab stop.
Keep tabs Inserts a tab character into the document and moves the cursor forward to the next tab stop when you press the Tab key.
Auto indent Lets you set the autoindent feature, which includes these options: