How should you select objects when using the stretch command?

Select objects at the side, where you want to stretch.

Select the object by clicking it or by creating a window from top left to bottom right enclosing the whole object.

objects inclosed in crossing window can be stretched.

Create your selection window from left to right if you want to select only objects completely within the selection window. Select objects right to left if you want any object touched by the window to be selected. Also objects completely selected will be moved while partially selected objects will be stretched where the window cut off.

You have to select the parts of the edges you want to select by the normal selection windows