In LaTeX there is a useful feature called invisible brackets which you use e.g. if you want to have a vertical line after a fraction spanning over the full height without the need to have also the corresponding vertical line before the fraction:
\left.\frac{1}{2}\right|_{subscript}
The trick is the “\left.” It looks like this:
In TLatex and TMathText, this is unfortunately not possible. Running
TLatex * l1 = new TLatex(0.2,0.5,"#left.#frac{1}{2}#right|_{subscript}");
l1->Draw();
results in
*ERROR: Operators “#left” and “#right” don’t match !
Would it be possible to have this feature in ROOT?