Compiling the following diagram results in three boxes, however, there should only be two.
@startditaa
+-------+
| Box 1 |
+-------+
+-------+
| Box 2 |
+-------+
@endditaa
As of 2025-03-03, this can be observed here.
In the result, there is a shallow empty box between the two specified boxes. Adding additional empty lines does not change the result. The result is the same as if there was no empty line at all.
It seems that empty lines are entirely ignored. An empty line does not change the vertical spacing (not only in this, but also in other pictures). Adding spaces on an empty line does not change the behavior. However, when adding a non-breaking space to an empty line, the result looks as it should without the non-breaking space.