Color Setting rememberred - checkbox not upon page reload

Here is the log entry I have right after installing colors:

Notice: Undefined index: in Drupal\colors\Form\ColorsSettingsForm->buildForm() (line 90 of //web/modules/colors/src/Form/ColorsSettingsForm.php) #0 //web/core/includes/bootstrap.inc(548): _drupal_error_handler_real(8, 'Undefined index...', '//web/m...', 90, Array) #1 //web/modules/colors/src/Form/ColorsSettingsForm.php(90): _drupal_error_handler(8, 'Undefined index...', '//web/m...', 90, Array) #2 [internal function]: Drupal\colors\Form\ColorsSettingsForm->buildForm(Array, Object(Drupal\Core\Form\FormState)) #3 //web/core/lib/Drupal/Core/Form/FormBuilder.php(514): call_user_func_array(Array, Array) #4 //web/core/lib/Drupal/Core/Form/FormBuilder.php(271): Drupal\Core\Form\FormBuilder->retrieveForm('colors_ui_setti...', Object(Drupal\Core\Form\FormState)) #5 //web/core/lib/Drupal/Core/Controller/FormController.php(74): Drupal\Core\Form\FormBuilder->buildForm('colors_ui_setti...', Object(Drupal\Core\Form\FormState)) #6 [internal function]: Drupal\Core\Controller\FormController->getContentResult(Object(Symfony\Component\HttpFoundation\Request), Object(Drupal\Core\Routing\RouteMatch)) #7 //web/core/lib/Drupal/Core/EventSubscriber/EarlyRenderingControllerWrapperSubscriber.php(123): call_user_func_array(Array, Array) #8 //web/core/lib/Drupal/Core/Render/Renderer.php(574): Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}() #9 //web/core/lib/Drupal/Core/EventSubscriber/EarlyRenderingControllerWrapperSubscriber.php(124): Drupal\Core\Render\Renderer->executeInRenderContext(Object(Drupal\Core\Render\RenderContext), Object(Closure)) #10 //web/core/lib/Drupal/Core/EventSubscriber/EarlyRenderingControllerWrapperSubscriber.php(97): Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->wrapControllerExecutionInRenderContext(Array, Array) #11 [internal function]: Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}() #12 //web/vendor/symfony/http-kernel/HttpKernel.php(144): call_user_func_array(Object(Closure), Array) #13 //web/vendor/symfony/http-kernel/HttpKernel.php(64): Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object(Symfony\Component\HttpFoundation\Request), 1) #14 //web/core/lib/Drupal/Core/StackMiddleware/Session.php(57): Symfony\Component\HttpKernel\HttpKernel->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #15 //web/core/lib/Drupal/Core/StackMiddleware/KernelPreHandle.php(47): Drupal\Core\StackMiddleware\Session->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #16 //web/core/modules/page_cache/src/StackMiddleware/PageCache.php(99): Drupal\Core\StackMiddleware\KernelPreHandle->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #17 //web/core/modules/page_cache/src/StackMiddleware/PageCache.php(78): Drupal\page_cache\StackMiddleware\PageCache->pass(Object(Symfony\Component\HttpFoundation\Request), 1, true) #18 //web/core/lib/Drupal/Core/StackMiddleware/ReverseProxyMiddleware.php(47): Drupal\page_cache\StackMiddleware\PageCache->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #19 //web/core/lib/Drupal/Core/StackMiddleware/NegotiationMiddleware.php(50): Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #20 //web/vendor/stack/builder/src/Stack/StackedHttpKernel.php(23): Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #21 //web/core/lib/Drupal/Core/DrupalKernel.php(652): Stack\StackedHttpKernel->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #22 //web/index.php(19): Drupal\Core\DrupalKernel->handle(Object(Symfony\Component\HttpFoundation\Request)) #23 {main}.

and the next after that:

Warning: Invalid argument supplied for foreach() in Drupal\colors\Form\ColorsSettingsForm->getDefaultFormElements() (line 200 of /web//modules/colors/src/Form/ColorsSettingsForm.php) #0 /web//core/includes/bootstrap.inc(548): _drupal_error_handler_real(2, 'Invalid argumen...', '/web//m...', 200, Array) #1 /web//modules/colors/src/Form/ColorsSettingsForm.php(200): _drupal_error_handler(2, 'Invalid argumen...', '/web//m...', 200, Array) #2 /web//modules/colors/src/Form/ColorsSettingsForm.php(94): Drupal\colors\Form\ColorsSettingsForm->getDefaultFormElements(Array) #3 [internal function]: Drupal\colors\Form\ColorsSettingsForm->buildForm(Array, Object(Drupal\Core\Form\FormState)) #4 /web//core/lib/Drupal/Core/Form/FormBuilder.php(514): call_user_func_array(Array, Array) #5 /web//core/lib/Drupal/Core/Form/FormBuilder.php(271): Drupal\Core\Form\FormBuilder->retrieveForm('colors_ui_setti...', Object(Drupal\Core\Form\FormState)) #6 /web//core/lib/Drupal/Core/Controller/FormController.php(74): Drupal\Core\Form\FormBuilder->buildForm('colors_ui_setti...', Object(Drupal\Core\Form\FormState)) #7 [internal function]: Drupal\Core\Controller\FormController->getContentResult(Object(Symfony\Component\HttpFoundation\Request), Object(Drupal\Core\Routing\RouteMatch)) #8 /web//core/lib/Drupal/Core/EventSubscriber/EarlyRenderingControllerWrapperSubscriber.php(123): call_user_func_array(Array, Array) #9 /web//core/lib/Drupal/Core/Render/Renderer.php(574): Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}() #10 /web//core/lib/Drupal/Core/EventSubscriber/EarlyRenderingControllerWrapperSubscriber.php(124): Drupal\Core\Render\Renderer->executeInRenderContext(Object(Drupal\Core\Render\RenderContext), Object(Closure)) #11 /web//core/lib/Drupal/Core/EventSubscriber/EarlyRenderingControllerWrapperSubscriber.php(97): Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->wrapControllerExecutionInRenderContext(Array, Array) #12 [internal function]: Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}() #13 /web//vendor/symfony/http-kernel/HttpKernel.php(144): call_user_func_array(Object(Closure), Array) #14 /web//vendor/symfony/http-kernel/HttpKernel.php(64): Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object(Symfony\Component\HttpFoundation\Request), 1) #15 /web//core/lib/Drupal/Core/StackMiddleware/Session.php(57): Symfony\Component\HttpKernel\HttpKernel->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #16 /web//core/lib/Drupal/Core/StackMiddleware/KernelPreHandle.php(47): Drupal\Core\StackMiddleware\Session->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #17 /web//core/modules/page_cache/src/StackMiddleware/PageCache.php(99): Drupal\Core\StackMiddleware\KernelPreHandle->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #18 /web//core/modules/page_cache/src/StackMiddleware/PageCache.php(78): Drupal\page_cache\StackMiddleware\PageCache->pass(Object(Symfony\Component\HttpFoundation\Request), 1, true) #19 /web//core/lib/Drupal/Core/StackMiddleware/ReverseProxyMiddleware.php(47): Drupal\page_cache\StackMiddleware\PageCache->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #20 /web//core/lib/Drupal/Core/StackMiddleware/NegotiationMiddleware.php(50): Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #21 /web//vendor/stack/builder/src/Stack/StackedHttpKernel.php(23): Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #22 /web//core/lib/Drupal/Core/DrupalKernel.php(652): Stack\StackedHttpKernel->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #23 /web//index.php(19): Drupal\Core\DrupalKernel->handle(Object(Symfony\Component\HttpFoundation\Request)) #24 {main}.