[NTG-context] Left and centered text on the same line

Good evening, How can I place left aligned and centered text on one line? So that the centered text is in the same place as with \startaligned[middle] I experimented with the following code: \startalignment[middle] I'm centered % this serves as a reference, its right in the middle of the paper \stopalignment % now to the tricky part \starttabulate[|lw(\dimexpr 0.5\textwidth\relax)|c|] \NC I'm left \NC I'm centered \NC \NR \NC I'm also left \NC I'm also centered \NC \NR \stoptabulate I tried various versions with the dimensions, subtracting \leftmarginwidth and what not. to no avail. The tabulate solution is always a tad off. What am I missing here? -Christian