Ohhh, is that why I keep pressing tab and it doesn't accept the prediction lately? I thought it was a bug. It feels weird for tab to double-indent when it could be accepting a prediction - I wonder if alt-tab to do a manual indent rather than accept the current prediction might be preferable?

Edit - On the other hand, a related issue is that if the prediction itself starts with whitespace, in that case it would be good if tab just indents like normal; otherwise you can't indent without accepting the prediction.