diff --git a/phpBB/adm/style/acp_ext_list.html b/phpBB/adm/style/acp_ext_list.html
index c5527c14bc..0b63302eed 100644
--- a/phpBB/adm/style/acp_ext_list.html
+++ b/phpBB/adm/style/acp_ext_list.html
@@ -60,7 +60,7 @@
 			<td style="text-align: center;"><a href="{enabled.U_DETAILS}">{L_DETAILS}</a></td>
 			<td style="text-align: center;">
 				<!-- BEGIN actions -->
-					<a href="{enabled.actions.U_ACTION}"<!-- IF enabled.actions.L_ACTION_EXPLAIN --> title="{enabled.actions.L_ACTION_EXPLAIN}"<!-- ENDIF -->>{enabled.actions.L_ACTION}</a>
+					<a href="{enabled.actions.U_ACTION}"<!-- IF enabled.actions.ACTION == 'REMOVE' --> style="color: #bc2a4d;"<!-- ENDIF --><!-- IF enabled.actions.L_ACTION_EXPLAIN --> title="{enabled.actions.L_ACTION_EXPLAIN}"<!-- ENDIF -->>{enabled.actions.L_ACTION}</a>
 					<!-- IF not enabled.actions.S_LAST_ROW -->&nbsp;|&nbsp;<!-- ENDIF -->
 				<!-- END actions -->
 			</td>
@@ -88,7 +88,7 @@
 			</td>
 			<td style="text-align: center;">
 				<!-- BEGIN actions -->
-					<a href="{disabled.actions.U_ACTION}"<!-- IF disabled.actions.L_ACTION_EXPLAIN --> title="{disabled.actions.L_ACTION_EXPLAIN}"<!-- ENDIF -->>{disabled.actions.L_ACTION}</a>
+					<a href="{disabled.actions.U_ACTION}"<!-- IF disabled.actions.ACTION == 'REMOVE' --> style="color: #bc2a4d;"<!-- ENDIF --><!-- IF disabled.actions.L_ACTION_EXPLAIN --> title="{disabled.actions.L_ACTION_EXPLAIN}"<!-- ENDIF -->>{disabled.actions.L_ACTION}</a>
 					<!-- IF not disabled.actions.S_LAST_ROW -->&nbsp;|&nbsp;<!-- ENDIF -->
 				<!-- END actions -->
 			</td>
diff --git a/phpBB/includes/acp/acp_extensions.php b/phpBB/includes/acp/acp_extensions.php
index 5bdb381d1b..de98bfadb1 100644
--- a/phpBB/includes/acp/acp_extensions.php
+++ b/phpBB/includes/acp/acp_extensions.php
@@ -838,10 +838,7 @@ class acp_extensions
 			{
 				$this->output_actions('enabled', [
 					'UPDATE' => $this->u_catalog_action . '&amp;action=update&amp;extension=' . urlencode($block_vars['META_NAME']),
-					'REMOVE' => [
-						'url' => $this->u_catalog_action . '&amp;action=remove&amp;extension=' . urlencode($block_vars['META_NAME']),
-						'color' => '#BC2A4D;',
-					]
+					'REMOVE' => $this->u_catalog_action . '&amp;action=remove&amp;extension=' . urlencode($block_vars['META_NAME']),
 				]);
 			}
 		}
@@ -922,10 +919,7 @@ class acp_extensions
 			{
 				$this->output_actions('disabled', [
 					'UPDATE' => $this->u_catalog_action . '&amp;action=update&amp;extension=' . urlencode($block_vars['META_NAME']),
-					'REMOVE' => [
-						'url' => $this->u_catalog_action . '&amp;action=remove&amp;extension=' . urlencode($block_vars['META_NAME']),
-						'color' => '#BC2A4D;',
-					]
+					'REMOVE' => $this->u_catalog_action . '&amp;action=remove&amp;extension=' . urlencode($block_vars['META_NAME']),
 				]);
 			}
 		}
@@ -997,6 +991,7 @@ class acp_extensions
 
 			$this->output_actions('disabled', array(
 				'ENABLE'		=> $this->u_action . '&amp;action=enable_pre&amp;ext_name=' . urlencode($name),
+				'REMOVE' => $this->u_catalog_action . '&amp;action=remove&amp;extension=' . urlencode($block_vars['META_NAME']),
 			));
 		}
 	}
@@ -1009,11 +1004,12 @@ class acp_extensions
 	*/
 	private function output_actions($block, $actions)
 	{
-		foreach ($actions as $lang => $url)
+		foreach ($actions as $action => $url)
 		{
 			$this->template->assign_block_vars($block . '.actions', [
-				'L_ACTION'			=> $this->user->lang('EXTENSION_' . $lang),
-				'L_ACTION_EXPLAIN'	=> (isset($this->user->lang['EXTENSION_' . $lang . '_EXPLAIN'])) ? $this->user->lang('EXTENSION_' . $lang . '_EXPLAIN') : '',
+				'ACTION'			=> $action,
+				'L_ACTION'			=> $this->user->lang('EXTENSION_' . $action),
+				'L_ACTION_EXPLAIN'	=> (isset($this->user->lang['EXTENSION_' . $action . '_EXPLAIN'])) ? $this->user->lang('EXTENSION_' . $action . '_EXPLAIN') : '',
 				'U_ACTION'			=> $url,
 			]);
 		}
diff --git a/phpBB/phpbb/composer/installer.php b/phpBB/phpbb/composer/installer.php
index 9910cb5a08..3e6d87d46f 100644
--- a/phpBB/phpbb/composer/installer.php
+++ b/phpBB/phpbb/composer/installer.php
@@ -152,7 +152,9 @@ class installer
 	{
 		if (!$io)
 		{
+			$this->restore_cwd();
 			$io = new null_io();
+			$this->move_to_root();
 		}
 
 		$this->generate_ext_json_file($packages);
@@ -184,6 +186,7 @@ class installer
 		catch (\Exception $e)
 		{
 			$this->restore_ext_json_file();
+			$this->restore_cwd();
 
 			throw new runtime_exception('COMPOSER_CANNOT_INSTALL', [], $e);
 		}
@@ -191,6 +194,7 @@ class installer
 		if ($result !== 0)
 		{
 			$this->restore_ext_json_file();
+			$this->restore_cwd();
 
 			throw new runtime_exception($io->get_composer_error(), []);
 		}
@@ -587,6 +591,7 @@ class installer
 				$repositories[] = [
 					'type' => 'composer',
 					'url' => $repository,
+					'canonical' => $this->packagist ? false : true,
 				];
 			}
 		}
diff --git a/phpBB/phpbb/composer/manager.php b/phpBB/phpbb/composer/manager.php
index d5fe8935cf..e36a32d1e9 100644
--- a/phpBB/phpbb/composer/manager.php
+++ b/phpBB/phpbb/composer/manager.php
@@ -89,7 +89,7 @@ class manager implements manager_interface
 		$managed_packages = array_merge($this->get_all_managed_packages(), $packages);
 		ksort($managed_packages);
 
-		$this->installer->install($managed_packages, array_keys($packages), $io);
+		$this->installer->install($managed_packages, [], $io);
 
 		$this->post_install($packages, $io);
 
diff --git a/tests/functional/extension_acp_test.php b/tests/functional/extension_acp_test.php
index ab02831209..a4d45506f4 100644
--- a/tests/functional/extension_acp_test.php
+++ b/tests/functional/extension_acp_test.php
@@ -76,7 +76,7 @@ class phpbb_functional_extension_acp_test extends phpbb_functional_test_case
 		$this->login();
 		$this->admin_login();
 
-		$this->add_lang('acp/extensions');
+		$this->add_lang(['acp/common', 'acp/extensions']);
 	}
 
 	public function test_list()
@@ -254,6 +254,7 @@ class phpbb_functional_extension_acp_test extends phpbb_functional_test_case
 
 		$form = $crawler->selectButton('Submit')->form();
 		$form['minimum_stability']->select('dev');
+		$form['repositories'] = 'https://satis.phpbb.com/';
 		$crawler = self::submit($form);
 		$this->assertContainsLang('CONFIG_UPDATED', $crawler->filter('div[class="successbox"] > p')->text());
 
@@ -264,4 +265,114 @@ class phpbb_functional_extension_acp_test extends phpbb_functional_test_case
 		// Ensure catalog has any records in extensions list
 		$this->assertGreaterThan(0, $crawler->filter('tbody > tr > td > strong')->count());
 	}
+
+	public function test_extensions_catalog_installing_extension()
+	{
+		// Lets check page 6 where 'Scroll Page' and 'Scroll To Top' should be listed
+		$crawler = self::request('GET', 'adm/index.php?i=acp_extensions&mode=catalog&start=100&sid=' . $this->sid);
+		$this->assertContainsLang('ACP_EXTENSIONS_CATALOG', $this->get_content());
+
+		// Get Install links for both extensions
+		$scrollpage_install_link = $crawler->filter('tr')->reduce(
+			function ($node, $i)
+			{
+				return (bool) (strpos($node->text(), 'Scroll Page') !== false);
+			}
+		)->selectLink($this->lang('INSTALL'))->link();
+
+		$scrolltotop_install_link = $crawler->filter('tr')->reduce(
+			function ($node, $i)
+			{
+				return (bool) (strpos($node->text(), 'Scroll To Top') !== false);
+			}
+		)->selectLink($this->lang('INSTALL'))->link();
+
+		// Attempt to install vse/scrollpage extension
+		$crawler = self::$client->click($scrollpage_install_link);
+		$this->assertContainsLang('EXTENSIONS_INSTALLED', $crawler->filter('.successbox > p')->text());
+		// Assert there's console log output
+		$this->assertStringContainsString('Installing vse/scrollpage', $crawler->filter('.console-output > pre')->text());
+
+		// Attempt to install vse/scrolltotop extension
+		$crawler = self::$client->click($scrolltotop_install_link);
+		$this->assertContainsLang('EXTENSIONS_INSTALLED', $crawler->filter('.successbox > p')->text());
+		// Assert there's console log output
+		$this->assertStringContainsString('Installing vse/scrolltotop', $crawler->filter('.console-output > pre')->text());
+
+		// Ensure installed extension appears in available extensions list
+		$crawler = self::request('GET', 'adm/index.php?i=acp_extensions&mode=main&sid=' . $this->sid);
+		$this->assertStringContainsString('Scroll To Top', $crawler->filter('strong[title="vse/scrolltotop"]')->text());
+		$this->assertStringContainsString('Scroll Page', $crawler->filter('strong[title="vse/scrollpage"]')->text());
+	}
+
+	public function test_extensions_catalog_updating_extension()
+	{
+		// Enable 'Scroll Page' extension installed earlier
+		$crawler = self::request('GET', 'adm/index.php?i=acp_extensions&mode=main&sid=' . $this->sid);
+		$extension_enable_link = $crawler->filter('tr')->reduce(
+			function ($node, $i)
+			{
+				return (bool) (strpos($node->text(), 'Scroll Page') !== false);
+			}
+		)->selectLink($this->lang('EXTENSION_ENABLE'))->link();
+		$crawler = self::$client->click($extension_enable_link);
+		$form = $crawler->selectButton($this->lang('EXTENSION_ENABLE'))->form();
+		$crawler = self::submit($form);
+		$this->assertContainsLang('EXTENSION_ENABLE_SUCCESS', $crawler->filter('.successbox')->text());
+
+		// Update 'Scroll Page' enabled extension
+		$crawler = self::request('GET', 'adm/index.php?i=acp_extensions&mode=main&sid=' . $this->sid);
+		$scrollpage_update_link = $crawler->filter('tr')->reduce(
+			function ($node, $i)
+			{
+				return (bool) (strpos($node->text(), 'Scroll Page') !== false);
+			}
+		)->selectLink($this->lang('EXTENSION_UPDATE'))->link();
+		$crawler = self::$client->click($scrollpage_update_link);
+		$this->assertContainsLang('EXTENSIONS_UPDATED', $crawler->filter('.successbox > p')->text());
+		// Assert there's console log output
+		$this->assertStringContainsString('Updating packages', $crawler->filter('.console-output > pre')->text());
+
+		// Ensure installed extension still appears in available extensions list
+		$crawler = self::request('GET', 'adm/index.php?i=acp_extensions&mode=main&sid=' . $this->sid);
+		$this->assertStringContainsString('Scroll Page', $crawler->filter('strong[title="vse/scrollpage"]')->text());
+	}
+
+	public function test_extensions_catalog_removing_extension()
+	{
+		$crawler = self::request('GET', 'adm/index.php?i=acp_extensions&mode=main&sid=' . $this->sid);
+
+		// Check if both enabled and disabled extensions have 'Remove' action available
+		$scrollpage_remove_link = $crawler->filter('tr')->reduce(
+			function ($node, $i)
+			{
+				return (bool) (strpos($node->text(), 'Scroll Page') !== false);
+			}
+		)->selectLink($this->lang('EXTENSION_REMOVE'))->link();
+
+		$scrolltotop_remove_link = $crawler->filter('tr')->reduce(
+			function ($node, $i)
+			{
+				return (bool) (strpos($node->text(), 'Scroll To Top') !== false);
+			}
+		)->selectLink($this->lang('EXTENSION_REMOVE'))->link();
+
+		// Test extensions removal
+		// Remove 'Scroll Page' enabled extension
+		$crawler = self::$client->click($scrollpage_remove_link);
+		$this->assertContainsLang('EXTENSIONS_REMOVED', $crawler->filter('.successbox > p')->text());
+		// Assert there's console log output
+		$this->assertStringContainsString('Deleting ext/vse/scrollpage', $crawler->filter('.console-output > pre')->text());
+
+		// Remove 'Scroll To Top' disabled extension
+		$crawler = self::$client->click($scrolltotop_remove_link);
+		$this->assertContainsLang('EXTENSIONS_REMOVED', $crawler->filter('.successbox > p')->text());
+		// Assert there's console log output
+		$this->assertStringContainsString('Deleting ext/vse/scrolltotop', $crawler->filter('.console-output > pre')->text());
+
+		// Ensure removed extensions do not appear in available extensions list
+		$crawler = self::request('GET', 'adm/index.php?i=acp_extensions&mode=main&sid=' . $this->sid);
+		$this->assertStringNotContainsString('Scroll Page', $this->get_content());
+		$this->assertStringNotContainsString('Scroll To Top', $this->get_content());
+	}
 }