The Fixed Constraint has been very buggy in my experience, and I want to share something I see that is clearly a bug.
I have here a sketch that contains several lines. They form a couple of polygons that are drawn to match a canvas in a project, so the dimensions are inserted just to get the shape to hold its shape. My goal is to draw some lines that are parallel to the longer lines and for me to specify the distance between those lines. I started by drawing them without applying any constraints:
Upon using the dimension tool, a whole polygon shifted toward one of the new lines. Because this polygon is supposed to match a canvas, I don't want it to move. I figured that a better way to do this would be to use the Fix constraint on the polygon so that it wouldn't move during the dimension tool. This colors the polygon green. From here, the behavior of the program feels inconsistent. Sometimes, the dimension against fixed geometry works as intended, shown on the upper polygon:
But sometimes, as seen in the lower polygon, a driven constraint is made. It shouldn't be driven, as I can click and hold this lower line and move it around, causing the driven dimension to update its value in real time.
I would expect a driven dimension to not move when dragged.
Another thing worth noting here is that the dimensions that were already on the polygon were not changed to the dark green color expected from driven dimensions. If you attempt to edit one of the constraint values, Fusion fails to solve and it produces an error message. Only if you delete the constraint and reapply it does Fusion warn you that it must be a driven constraint (as expected, because I'm applying a dimension between fixed lines).
I've attached the offending sketch on a fresh project. The vertical line is a projected line in my main project, so I fixed it in this example. Like I said, the behavior is inconsistent. Fusion seems to have a hard time solving anything involving the Fix constraint correctly.
