There's a very basic/obvious bug when constraining sketches. Constraints are removed but the unconstrained lines stay white. Very simple to reproduce.

[benrYVMRB]

I've noticed that sometimes a sketch will show as fully constrained (white lines) when it is not actually.

This is very problematic.

I've found a simple way to recreate this bug, See Video. 

1. Create fully constrained square at the origin.

2. Create a line off one edge, with a horizontal constraint and a dimension to set it's location.

2a. Add a circle with mid-point constraint to the line.

3. Connect the line to the opposite edge of the square. Fusion tries to add in a perpendicular constraint as well, which would over-constrain the sketch, this likely is what causes the bug.

4. Delete the horizontal constraint. Note that the line remains white, but the angle can be changed (BUG).

5. Repeat the process with a second line, but this time don't add the horizontal constraint, instead allow the perpendicular constraint to be added automatically. 

6. Delete the new perpendicular constraint. Note that the second line remains white (BUG) but now the first line turns blue (BUG).

How such a low-level, fundamental bug not been fixed already is beyond me.