Text-to-text alignment doesn't work when using Right-to-Left text direction?

The paragraph formatting option “Alignment” under “Text-to-text” is not reflected on the document when the text-direction is set to Right-to-Left.

I am using Arabic text, and when I have letters that are bit long towards the bottom, those letters get cut off. So I increased the line spacing, and then set the alignment to middle, but it only works when the text direction is set to Left-to-Right.