This construction in src/views/uploadButton.phpuploadButton.php
<span><?= Yii::t('app', 'Select file...') ?></span>
generates exception every time when FileUpload::run() execute if there is no the 'app' message category.
Probably, 'fileupload' message category is more suitable in this case.
This construction in src/views/uploadButton.phpuploadButton.php
<span><?= Yii::t('app', 'Select file...') ?></span>
generates exception every time when FileUpload::run() execute if there is no the 'app' message category.Probably, 'fileupload' message category is more suitable in this case.