Rhombus

After selecting the tool, click two points in the drawing pad, a segment AB will be created. This the first side of your rhombus.

Note that size and position of the circle change with A and B.

Point C should be freely movable on the circle.

AC will be another side of your rhombus.

To construct a line through C parallel to AB, click point C and segment AB. Similarly, construct another parallel line with point B and segment AC. These two lines will define the fourth vertex of your rhombus.

When the pointer is over the intersection, both lines should be highlighted. When you click on it, a point D will be added. This is the fourth vertex of the rhombus.

Click the four points to make a polygon. Drag A, B or C to check that the polygon remains a rhombus.

Choose the mode "Show/hide object", then click on the parallel lines and circle. These objects will remain highlighted. They will be hidden when you leave this mode, say, when return to the mode of moving objects.

Another way of hiding objects is simply right click individual objects and check the option "show objects" from the contextual menu.