Summary of Changes

• Removed the if filterButton condition for PHP loading of filter fields.

• Why: In Joomla 3.6.5 in list views (backend) one could easily hide the button "Search Tools" but show the filter fields permanentely by sending the options filterButton and filtersHidden to the JLayout like this

echo JLayoutHelper::render('joomla.searchtools.default', array('view' => $this, 
'options' => array('filterButton' => false, 'filtersHidden' => false)
)); 

• Since Joomla 3.7 not only the button is hidden but also all filters THAT ARE NOT LOADED BY PHP at all. No chance to show the filters permanentely if option 'filterButton' => false. Option 'filtersHidden' is senseless.

Testing Instructions

• Testing with a core component that has a list view with search tools, e.g. com_content > Articles.
• Open /administrator/components/com_content/views/articles/tmpl/default.php.
• Change line 59 ( https://github.com/joomla/joomla-cms/blob/3.7.0/administrator/components/com_content/views/articles/tmpl/default.php#L59 )

echo JLayoutHelper::render('joomla.searchtools.default', array('view' => $this, 
'options' => array('filterButton' => false, 'filtersHidden' => false)
)); 

• In backend go to administrator/index.php?option=com_content&view=articles

• You'll see no filter fields and no button. If you want check HTML source code that filters are not loaded at all.

• Now the same test with Joomla 3.6.5 in line 46 if you're not convinced: https://github.com/joomla/joomla-cms/blob/3.6.5/administrator/components/com_content/views/articles/tmpl/default.php#L46

• No button but filters are always visible.

• Apply patch.

• Try again in Joomla 3.7