Box selection is a feature that has been in Visual Studio
for a while (although not many people knew about it). It allows you to
select a rectangular region of text within the code editor by holding down the
Alt key while selecting the text region with the mouse. With VS 2008 you
could then copy or delete the selected text.
VS 2010 now enables several more capabilities with box
Text Insertion: Typing with box selection now allows you to
insert new text into every selected line
Paste/Replace: You can now paste the contents of one box
selection into another and have the content flow correctly
Zero-Length Boxes: You can now make a vertical selection
zero characters wide to create a multi-line insert point for new or copied text
These capabilities can be very useful in a variety of
scenarios. Some example scenarios: change access modifiers
(private->public), adding comments to multiple lines, setting fields, or
grouping multiple statements together.