Steps to reproduce the issue

create a jform xml definition with two editor fields
for example open file administrator/components/com_content/models/article.xml
Add a new field nodes in the first fieldset above the field with name "articletext"
< field name="test1" type="editor"
label="Editor_No_Module_Pagebreak"
filter="JComponentHelper::filterText" buttons="true" hide="module,pagebreak" />
Make sure that tinymce is default editor on the Joomla! installation.
Open file administrator\components\com_content\views\article\tmpl\edit.php and replace

<?php echo $this->form->getInput('articletext'); ?> at line 88
with
<?php echo $this->form->getInput('test1'); ?>
<?php echo $this->form->getInput('articletext'); ?>
in order to display the new editor field in article edit form.

Open an article in the edit view in the administration

Expected result

Display two editor fields in the article edit view. The first one having the editor xtd buttons article, image and readmore, the second one having the editor xtd buttons article, image, readmore, module and pagebreak

Actual result

Both editor fields have the same editor xtd buttons (article, iamge and readmore).

System information (as much as possible)

Joomla! 3.5.0 on different servers i.e. local host with XAMPP, PHP 5.5.30

Additional comments

On Joomla! prior to 3.5.0 it was possible to have multiple editors in a edit view with different buttons. The static varialbe $declaredJs in the function onDisplay in the plugin/editors/tinymce/tinymce.php, which was introduced with code changes made for Joomla! 3.5.0, prevents the plugin from adding the proper editor xtd buttons as defined in the xml file individually for each editor instance.
I have devoloped custom editor xtd buttons for my Joomla! component Visforms. I have multiple editors fields in the administration edit view and I need to display the custom editor xtd button only in some of this editor fields. This feature is broken since Joomla! 3.5.0 and I can see now way to fix it inside the Visforms code.

Regards,
Aicha