Error pack

[WinterSilence]

Prerequisites

• I have searched for similar issues in both open and closed tickets and cannot find a duplicate.
• The issue still exists against the latest master branch of yii2-export.
• This is not an usage question. I confirm having gone through and read the documentation and demos.
• This is not a general programming / coding question. (Those should be directed to the webtips Q & A forum).
• I have attempted to find the simplest possible steps to reproduce the issue.
• I have included a failing test as a pull request (Optional).

Errors:

1. can't replace your default classes in class attribute, merged classes generate invalid style:

<?= ExportMenu::widget([
'dropdownOptions' => ['class' => ['btn-secondary']]
]) ?>

generate class="btn btn-secondary btn-outline-secondary dropdown-toggle".
2. you ignore ExportMenu::$caption

Expected behavior and actual behavior

...

Environment

Browsers

• Google Chrome
• Mozilla Firefox
• Internet Explorer
• Safari

Operating System

• Windows
• Mac OS X
• Linux
• Mobile

Libraries

• jQuery version: no matter
• yii2-export version: master

Isolating the problem

• This bug happens on the demos page
• The bug happens consistently across all tested browsers
• This bug happens when using yii2-export without other plugins.