First element of an array of multiline strings shows text vertically when uncollapsed

Created by: ghost

Godot version: Godot 3.1 stable

OS/device including version: Windows 10 Version 1809

Issue description: When making an array of multiline strings with only one element, the first element will render all of its text vertically in the inspector if you collapse and then uncollapse the array. Clicking on the text box will reset it back to normal. This doesn't happen if there is more than one element in the array.

Steps to reproduce:

1. Create an exported var with the hints Array, String, and MULTILINE.
2. Add exactly one element and input some text.
3. Collapse the array in the inspector and then uncollapse.
4. The text will be displayed vertically until you click on the text box.