Two suggestions about Wall parameters and Mouse Cross Hair.

[Mussawar]

1) Length of a wall could optionally be locked; Means no matter the wall is moved or angled, its length is remain fixed. This will help to draw some irregular plans and home boundaries.
2) Cross Hair line with mouse pointer is visible only in rulers area it should be visible from pointer to the edges, covering the whole work area. This will help to easily align various objects.
[:)]