diff --git a/src/Application/UI/Presenter.php b/src/Application/UI/Presenter.php
index de065d83a..24f9071ac 100644
--- a/src/Application/UI/Presenter.php
+++ b/src/Application/UI/Presenter.php
@@ -1236,7 +1236,8 @@ private function initGlobalParameters()
 		$params = $this->request->getParameters();
 		if ($this->isAjax()) {
 			$params += $this->request->getPost();
-		} elseif (isset($this->request->post[self::SIGNAL_KEY])) {
+		}
+		if (isset($this->request->post[self::SIGNAL_KEY])) {
 			$params[self::SIGNAL_KEY] = $this->request->post[self::SIGNAL_KEY];
 		}
 
diff --git a/tests/Application/Presenter.parameters.phpt b/tests/Application/Presenter.parameters.phpt
index e349ae917..c235feca8 100644
--- a/tests/Application/Presenter.parameters.phpt
+++ b/tests/Application/Presenter.parameters.phpt
@@ -87,3 +87,13 @@ test(function () {
 	)));
 	Assert::same(array('', 'foo'), $presenter->getSignal());
 });
+
+test(function () {
+	//AJAX: signal in POST overwriting empty GET
+	$presenter = createPresenter();
+	$presenter->ajax = TRUE;
+	$presenter->run(new Application\Request('Foo', 'POST', array('do' => NULL), array(
+		'do' => 'foo'
+	)));
+	Assert::same(array('', 'foo'), $presenter->getSignal());
+});