Signs with colour formatting (§) can't have new lines

Verification builds:
1.2.5 Retail | Windows 10 Yes

Summary:
When adding formatted text to a sign, the return key does not behave normally. Pressing enter either does nothing, or starts to delete text. The sign will also overwrite text at the end of the sign when using the left/right keys to edit.

Steps to Reproduce:

1. Create a sign

2. First line, type Hello §a (alt + 0167)

3. Hit enter

Observed Results:
The return character does not work, if you keep trying the text will start to delete.

Expected Results:
Formatted text on a sign should be possible.

Screenshots/Videos attached: Yes

Notes: