Steps to reproduce

1. Install Ibexa DXP v4.4
2. Add enough content to fill the content tree
3. Open the dropdown menu in the last content in the content tree
4. Move the mouse cursor a bit to the left (so that the mouse is still on the content tree) and then scroll down

Result

The dropdown does not move with its content object but stays at the same position.

See the screenshot, where the clicked dots are still red and "Target" is highlighted because that is where the mouse currently hovers:

 
When you move the mouse cursor to the right, the drop-down menu returns to the correct position.

Expected result

Dropdown menu should follow its content when scrolling.