### Steps to reproduce

1. Create a work item

2. Set a start or end date - not both

3. View the work item in gantt chart


### What is the buggy behavior?

* The bar in the gantt chart is shown as a one day solid block


Begin of the insertion<img class="op-uc-image op-uc-image_inline" src="/api/v3/attachments/177202/content">

End of the insertion ### What is the expected behavior?

1. In previous versions a color gradient to the left to transparent for WPs without start date or to the right for WPs without due date was shown


Begin of the insertion<img class="op-uc-image op-uc-image_inline" src="/api/v3/attachments/177203/content">

End of the insertion ### Important note

_Please make it look as before to avoid confusions to non existing start or due dates._

### Screenshots and other files

_Sorry, no old version avaiable for me anymore._

### Environment information

**OpenProject installation type**

* [x] Hosted cloud edition
* [ ] Packaged installation
* What distribution?

* [ ] Docker All-in-one container
* [ ] Docker-compose installation
* [ ] Other (please specify)

**OpenProject version**

_Newest version_

**Browser**

* [x] Chrome
* [ ] Firefox
* [ ] Safari
* [ ] Mobile Safari
* [ ] Other (please specify)