The horizontal axis labels in the column renderer chart example aren't positioned correctly. In my own code I've tried all the TextAnchor options and they all look wrong. I poked around in CartesianAxis.drawHorizontalLabels(), and it seems like the following condition is backwards:

if (!vertical) {
x = Math.floor(point.getX() - (bbox.getHeight() / 2.0));
} else {
x = Math.floor(point.getX() - (bbox.getWidth() / 2.0));
}

but I haven't had time to investigate further. Here's a screenshot from the GXT explorer app:gxt_chart_labels_bug.png