### Context

We've received repeated user feedback about users not realising this list is scrollable.

Originally, this was meant to be a nested menu (the main options first, and secondary less-used options such as 'Duplicates' and 'Blocked by' at a second level); however, this nested dropdown menu is not available in Rails. We therefore decided to make it a flat list, leading to this problem.

### Steps to reproduce

* Go to a work package

* Go to the Relations tab

* Click on the "+ Relation" button


### What is the buggy behavior?

* The dropdown list has a max-height of 450px, which cuts off the list cleanly after the sixth item.

* The user does not realise that there are other options below, visible on scroll


### What is the expected behavior?

* Change the max-height of dropdown list to Begin of the insertion420px,End of the insertion Begin of the deletion 470px,End of the deletion which Begin of the insertioncuts offEnd of the insertion Begin of the deletion showsEnd of the deletion a bit of the Begin of the insertion5th element.End of the insertion Begin of the deletion next elementEnd of the deletion

* The user realises there is something below, visible on scroll Begin of the insertion

* _Exact number to be determined._End of the insertion


### Screenshots and other files

<img class="image_resized op-uc-image op-uc-image_inline" style="width:865px;" src="/api/v3/attachments/403044/content">

### Environment information

Community
**OpenProject 15.4**

**Browser:**
Firefox Mac

**Language**
EN