Situation

I have a plain text file where indentation is important.

line 1
  line 1.1 (indented two spaces)
  line 1.2 (indented two spaces)
    line 1.2.3 (indented four spaces)

In Visual Studio 2008, when I pressed enter, the next line would also be indented four spaces.

However, in Visual Studio 2010, when I press enter, the next line is indented one tab.

Question

Does anybody know where, in the mountain of preferences under Tools > Options, I can return to the way that Visual Studio 2008 worked?

Under Options > Text Editor > Plain Text > Tabs, I see the following:

If I select "None", then I get no indentation when I move to the next line. If I select "Block", then I get TAB indentation (even though the previous line is spaces).

In Visual Studio 2008, my indentation is set to "Block", and I get spaces.

I have no idea what "Smart" indenting is, or why it is disabled.