Grid rotation problem & request

[Lutz Pietschker]

I often have to digitize town plans, meaning I have to draw a series of mostly orthogonal polygons along some oblique axis (the street to which the "polygons" - houses - are oriented). To enploy the 90° locking (shift-lock) it would be useful to rotate the canvas by arbitrary angles OR to rotate the grid - the latter seems more intuitive to me.

I found that in fact I can rotate the grid, but only each axis by itself (in advanced mode) - not the complete orthogonal standard grid, and I have to calculate the angles myself to make the axes orthogonal. The rotation controls are there but grayed ot when I am in standard grid mode (see screenshot). This is one of the things in AD where I find more options than I will ever need, but not the most simple and (to me) obvious one. Maybe I am overlooking something completely obvious, but I cannot see the reason for that limitation. How can I rotate the standard grid (both axes together) by arbitrary amounts? If not, why not?

Or, to make it a request: Please unlock the rotation control for the standard grid.