Why form submit opens new window/tab?

Question

I found a lot of questions "How to open form result in new window", but I'm facing opposite problem.

I have form:

<form:form method="post" commandName="search">
    ...
    <input type="submit" value="Search" />
</form>

Then I have controller with handling method

@RequestMapping(value = "/search.form", method = RequestMethod.POST)
public String submit( @Valid final SearchObject searchObject, final BindingResult bindingResult ) {
    if ( bindingResult.hasErrors() ) return "forms/search";
    return "redirect:/A/result.form";
}

Everything works fine, except the fact that result is opened in new window/tab.

Solution that I found and is working is to add target attribute:

<form:form method="post" commandName="search" target="_self">

But _self is default AFAIK.

I'm wondering why is that happening.

I checked generated HTML and it seems to me ok:

<form id="search" action="/myApp/A/search.form" method="post">

edit added headers

Content-Language    en-US
Content-Length  0
Date    Thu, 22 Mar 2012 16:29:13 GMT
Location    http://localhost:8080/myApp/A/result.form
Server  Apache-Coyote/1.1
Request Headersview source
Accept  text/html,application/xhtml+xml,application/xml;q=0.9,*/ *;q=0.8
Accept-Encoding gzip, deflate
Accept-Language en-us,en;q=0.5
Connection  keep-alive
Cookie  JSESSIONID=E9ACB44C4ED3814814ABE7D96C90135C; GUEST_LANGUAGE_ID=cs_CZ; COOKIE_SUPPORT=true
Host    localhost:8080
Referer http://localhost:8080/myApp/A/search.form
User-Agent  Mozilla/5.0 (Windows NT 6.1; WOW64; rv:11.0) Gecko/20100101 Firefox/11.0
Response Headers From Cache
Content-Language    en-US
Content-Length  0
Date    Thu, 22 Mar 2012 16:29:13 GMT
Location    http://localhost:8080/myApp/A/result.form
Server  Apache-Coyote/1.1
Request Headers From Upload Stream
Content-Length  64
Content-Type    application/x-www-form-urlencoded


GET sessions.form

200 OK

localhost:8080

309 B

::1:8080


6ms
HeadersResponseCacheHTML
Content-Language    en-US
Content-Length  309
Content-Type    text/html;charset=utf-8
Date    Thu, 22 Mar 2012 16:29:13 GMT
Server  Apache-Coyote/1.1
Request Headersview source
Accept  text/html,application/xhtml+xml,application/xml;q=0.9,*/ *;q=0.8
Accept-Encoding gzip, deflate
Accept-Language en-us,en;q=0.5
Connection  keep-alive
Cookie  JSESSIONID=E9ACB44C4ED3814814ABE7D96C90135C; GUEST_LANGUAGE_ID=cs_CZ; COOKIE_SUPPORT=true
Host    localhost:8080
Referer http://localhost:8080/myApp/A/search.form
User-Agent  Mozilla/5.0 (Windows NT 6.1; WOW64; rv:11.0) Gecko/20100101 Firefox/11.0

edit 2 added method for result.form

@RequestMapping(value = "/result.form", method = RequestMethod.GET)
public String result() {
    return "forms/result";
}

My controller class starts with:

@Controller
@RequestMapping(value = "/A")
public class AController {

Answer 1

Problem was in base tag. I had intentionally target="_blank" in tag, probably because I copied the example from w3schools :-/