Comment 4 for bug 182282

This is primarily because of the word "(Optional)". It makes the label cell taller, which makes the gap between the text field and the checkbox greater.

"(Optional)" looks wrong in its current position anyway, so I think the best fix is to move "(Optional)" to the right of all single-line text fields to which it applies in Launchpad. (For multi-line fields, it should stay where it is.)