'Drop component here' text is cut off

The 'Drop component here' text in empty containers is cut off by default. None of the empty containers is rendered high enough to contain the text (see screenshot).

Strange enough, this issue does not manifest itself in the online sales demo (cms.demo.onehippo.com). Yet it is present in the archetype project.

Steps to reproduce:
1. create a new project from archetype 3.0.1
2. build and run the project
3. in Essentials, add the 'News' feature
4. rebuild and restart
5. login to the CMS as admin
6. edit the only channel

Expected: all empty containers are high enough to fit their 'Drop component here' text
Actual: in each empty container, the 'Drop component here' text is cut off