Visual Studio IDE Supports CTRL-K+CTRL-D keyborad command to indent the code. This is very useful to check the HTML web-formedness.
When you do CTRL-K+CTRL-D on the HTML code (note: in HTML view of Web FORM) , it tries to indent the HTML. if everything is OK then it just keep one HTML tag in a line.
So if there are unnecessary / unmatched HTML tags then that are put in the same line.