<!-- Please fill in each section below, otherwise, your issue will be closed. This info allows django CMS maintainers to diagnose (and fix!) your issue as quickly as possible. --> ## Description The CSS settings for the Column widget are unresponsive to mouse input. <!-- If this is a security issue stop immediately and follow the instructions at: http://docs.django-cms.org/en/latest/contributing/development-policies.html#reporting-security-issues --> ## Steps to reproduce 1. Create a page and click on edit 2. Select the Column widget. 3. Try and edit the css settings with the mouse (image attached) to see the error. <!-- Clear steps describing how to reproduce the issue. Steps to reproduce the behavior: 1. Go to '...' 2. Click on '....' 3. Scroll down to '....' 4. See error --> ## Expected behaviour CSS settings should respond properly to mouse input. <!-- A clear and concise description of what you expected to happen. --> ## Actual behaviour CSS Settings are unresponsive. <!-- A clear and concise description of what is actually happening. --> ## Screenshots  <!--If applicable, add screenshots to help explain your problem. --> ## Additional information (CMS/Python/Django versions) djang-cms==3.8 <!-- Add any other context about the problem such as environment, CMS/Python/Django versions, logs etc. here. -->