Trying to render two text strings on alternating lines and determining glyph height.

[ChrisW67]

I had noticed something similar but could not exploit it to get the expected result.

As I understand the Tibetan script the stacks are made of glyphs that can either be subscripted below existing ones, or superscripted above existing ones. Does your example have a superscripted glyph that might be the cause of the negative?

[houzi]

Tibetan glyph stacks can often have root letters with both superscribed and subscribed letters. Thanks for your input, I will try to remove the superscribed glyph and see how the rectangle changes.