Shrink the bottom section

[HenrikeW]

The bottom section takes up a lot of space right now which is unnecessary. We should make it smaller as much as possible without loosing any functionality.
Ways to do that could be:

• remove the heading and instead replace the plus on the button with an explanatory text (like "Add row" or similar)
• don't let the "You have unsaved changes" warning take up space when it's not shown

Maybe there is more, this has to be explored

[ghost]

Good suggestion. Perhaps we would even make the bottom section not stay on top all the time? If we some time are going to support mobiles properly that is probably something we need to handle.