instead of behind them: they often aren't visible at the edge of the screen ...
Oh, please don*t. This would disturb the natural or usual reading/selection process.
Why not simply
>This would disturb the natural or usual reading/selection process.
The width is indeed causing problems:
I almost have to position a ruler at the screen to determine the gebruiksaanwijzing (operating manual) that I'd like to have inserted.
Now that I've worked out what he's talking about (the promper), I agree with alwayslock here – I don't really use the numbers, because by the time you've worked out which one you need, it would have been quicker just to type it.
Offering an option to place them before the prompt text (preferred) or narrowing the window to the max prompt text width are excellent ideas.