How to draw a line between the same apexes of two rectangles?

Question

I want to emphasize a part of the text (in the right column) with

1. overstating it
2. linking the two rectangles' apexes with four lines.

How can I accomplish Step 2?

The red lines in the pic had been drawn with Paint to indicate what I want to do. The emphasized part of text is hidden due to privacy.

What I have done:

1. Selected the extract in the text - Rectangle selection tool
2. Created another layer from it
3. Moved and overstated the new layer
4. Tried to create a line between two same edges - Line tool

...but it didn't snap to the lower rectangle's side.

Answer 1

Not knowing how you are drawing the rectangles here is what I will suggest:

1. Where you want the first rectangle, create a selection with rectangular marquee tool
2. While the selection is still active, drag guides from the left and from the top to snap to the edges of the selection, you should have four guides intersecting at four corners of the selection
3. Now, use the tool you want to draw the rectangle snapping to the guides
4. Repeat steps 1-3 for the second rectangle
5. There should now be guides at all the corners of the rectangles, when you draw lines they will snap to the guides. If it does not snap, check View/Snap To settings and put a check mark in those options