Switched to use display:none in extra_tags_for_form method.

The use of `display:inline` with the content_tag call in the
extra_tags_for_form method potentially causes display issues with some
browsers, namely Internet Explorer. IE's behaviour of not collapsing
the line height on divs with ostensibly no content means that the
automatically added div containing the hidden authenticity_token, utf8
and _method form input tags may interfere with other visible form
elements in certain circumstances. The use of `display:none` rather
than `display:inline` fixes this problem.

Fixes #6403

actionview/CHANGELOG.md

@@ -1,3 +1,9 @@
+*   Use `display:none` instead of `display:inline` for hidden fields
+
+    Fixes #6403
+
+    *Gaelian Ditchburn*
+
 *   The `video_tag` helper accepts a number as `:size`
 
     The `:size` option of the `video_tag` helper now can be specified

actionview/lib/action_view/helpers/form_helper.rb

@@ -51,7 +51,7 @@ module Helpers
     # The HTML generated for this would be (modulus formatting):
     #
     #   <form action="/people" class="new_person" id="new_person" method="post">
-    #     <div style="margin:0;padding:0;display:inline">
+    #     <div style="display:none">
     #       <input name="authenticity_token" type="hidden" value="NrOp5bsjoLRuK8IW5+dQEYjKGUJDe7TQoZVvq95Wteg=" />
     #     </div>
     #     <label for="person_first_name">First name</label>:
@@ -81,7 +81,7 @@ module Helpers
     # the code above as is would yield instead:
     #
     #   <form action="/people/256" class="edit_person" id="edit_person_256" method="post">
-    #     <div style="margin:0;padding:0;display:inline">
+    #     <div style="display:none">
     #       <input name="_method" type="hidden" value="patch" />
     #       <input name="authenticity_token" type="hidden" value="NrOp5bsjoLRuK8IW5+dQEYjKGUJDe7TQoZVvq95Wteg=" />
     #     </div>
@@ -315,7 +315,7 @@ module FormHelper
       # The HTML generated for this would be:
       #
       #   <form action='http://www.example.com' method='post' data-remote='true'>
-      #     <div style='margin:0;padding:0;display:inline'>
+      #     <div style='display:none'>
       #       <input name='_method' type='hidden' value='patch' />
       #     </div>
       #     ...
@@ -333,7 +333,7 @@ module FormHelper
       # The HTML generated for this would be:
       #
       #   <form action='http://www.example.com' method='post' data-behavior='autosave' name='go'>
-      #     <div style='margin:0;padding:0;display:inline'>
+      #     <div style='display:none'>
       #       <input name='_method' type='hidden' value='patch' />
       #     </div>
       #     ...

actionview/lib/action_view/helpers/form_tag_helper.rb

@@ -722,7 +722,7 @@ def extra_tags_for_form(html_options)
 
           enforce_utf8 = html_options.delete("enforce_utf8") { true }
           tags = (enforce_utf8 ? utf8_enforcer_tag : ''.html_safe) << method_tag
-          content_tag(:div, tags, :style => 'margin:0;padding:0;display:inline')
+          content_tag(:div, tags, :style => 'display:none')
         end
 
         def form_tag_html(html_options)

actionview/test/activerecord/form_helper_activerecord_test.rb

@@ -59,7 +59,7 @@ def test_nested_fields_for_with_child_index_option_override_on_a_nested_attribut
   protected
 
   def hidden_fields(method = nil)
-    txt =  %{<div style="margin:0;padding:0;display:inline">}
+    txt =  %{<div style="display:none">}
     txt << %{<input name="utf8" type="hidden" value="&#x2713;" />}
     if method && !%w(get post).include?(method.to_s)
       txt << %{<input name="_method" type="hidden" value="#{method}" />}

actionview/test/template/form_helper_test.rb

@@ -3023,7 +3023,7 @@ def test_form_for_only_instantiates_builder_once
   protected
 
   def hidden_fields(method = nil)
-    txt =  %{<div style="margin:0;padding:0;display:inline">}
+    txt =  %{<div style="display:none">}
     txt << %{<input name="utf8" type="hidden" value="&#x2713;" />}
     if method && !%w(get post).include?(method.to_s)
       txt << %{<input name="_method" type="hidden" value="#{method}" />}

actionview/test/template/form_tag_helper_test.rb

@@ -14,7 +14,7 @@ def hidden_fields(options = {})
     method = options[:method]
     enforce_utf8 = options.fetch(:enforce_utf8, true)
 
-    txt =  %{<div style="margin:0;padding:0;display:inline">}
+    txt =  %{<div style="display:none">}
     txt << %{<input name="utf8" type="hidden" value="&#x2713;" />} if enforce_utf8
     if method && !%w(get post).include?(method.to_s)
       txt << %{<input name="_method" type="hidden" value="#{method}" />}