WARNING
Related to WP 2.2.2 but this version number could not be selected while submitting the ticket in Trac.
Maybe a classic defect in WP since ages but this is a very specific thing in the process applied on Page and Post Source.
source:
<label>...</label>
<input ... />
is the same in output html source.
source:
<label>...</label><input ... />
differs in output html source:
<label>...</label>
<br/>
<input ... />
this is nothing in specific maybe but compare it with a combination of <label> and <textarea>. there it is the other way round:
source:
<label>...</label>
<textarea> ... </textare>
will become in output html source:
<label>...</label>
<br/>
<textarea> ... </textare>
and source:
<label>...</label><textarea> ... </textare>
is the same in output html source.
so you can see that it is exactly the other way round. this is an inconsitency that leads to confusion for Authros and Developers.