in v9, backspace causes cell to become section style

Question

In the front end of v9, in any given cell that contains content, if I hit backspace to clear the content until there is nothing left, and then hit backspace one more time, the cell becomes a 'section'.

Is this a new feature? How do I use it?

Edit

Would someone verify this effect in the comments?

Answer 1

In Version 9, in cells with Title, Subtitle, Subsubtitle or Section, Subsection, Subsubsection, ..., Subsubsubsubsection (perhaps others) style, Backspace in the beginning of the cell changes the cell style to the style of the next level up the hierarchy (e.g., Subsubsection > Subsection > Section). Similarly, Tab changes the style of the cell to that of the lower level; e.g., Section > Subsection > Subsubsection > ...

StyleKeyMapping suboption in the style definitions controls the behaviour in response to Backspace and Tab

  somestyles ={"Title", "Subtitle", "Subsubtitle",   "Section", "Subsection", "Subsubsection",
  "Subsubsubsection",   "Subsubsubsubsection"}; 
  Grid[ Prepend[{Style[#,#], Column[CurrentValue[{StyleDefinitions, #, StyleKeyMapping}], 
        Center]} & /@ somestyles, 
   Style[#, Bold, 16] & /@ {"Style", "StyleKeymapping"}], Dividers -> All]