bug #3789 Fixed an error related to filters when saving entities (jav…

…iereguiluz)

This PR was merged into the 3.0.x-dev branch.

Discussion
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Fixed an error related to filters when saving entities

Fixes #3587 and #3772.

Commits
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5938815 Fixed an error related to filters when saving entities

src/Factory/FormFactory.php

@@ -72,7 +72,7 @@ public function createFiltersForm(FilterCollection $filters, Request $request):
     {
         $filtersForm = $this->symfonyFormFactory->createNamed('filters', FiltersFormType::class, null, [
             'method' => 'GET',
-            'action' => $request->query->get('referrer'),
+            'action' => $request->query->get('referrer', ''),
             'ea_filters' => $filters,
         ]);