Wrong linespace with tabu

Question

Possible Duplicate:
Vertical alignment in multicol

I have the following example:

\documentclass{article}
\usepackage{tabu}
\begin{document}
\tabulinesep=6pt
\begin{tabu} to \textwidth{|X[.5]|X[.5]|}
 TTTTTTTTTT & TTTTTTTTTT \\
 TTTT ggggg & TTTT ggggg \\
 TTTTTTTTTT & TTTTTTTTTT \\
\end{tabu}
\vspace{2ex}

\begin{tabu} to \textwidth{|X[.5]|X[.5]|}
 \hline
 TTTTTTTTTT & TTTTTTTTTT \\
 \hline
 TTTT ggggg & TTTT ggggg \\
 \hline
 TTTTTTTTTT & TTTTTTTTTT \\
 \hline
\end{tabu}
\end{document}

This is the result:

The problem now is, that the vertical space between the lines is not the same in each line. The space between the baseline of the second row and the ascender of the Letter "T" in the third row is bigger than the same length that results when you compare the first to the second row. This is because of the letter "g". So the distance gets calculeted from the descender of this letter which results in a bigger spacing.

Any ideas how I can avoid this?