Stretching with multiple crossing-boxes does not seem to work.  Here is an example sequence of actions:

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stretch [Enter]

c [Enter]    (c for crossing)

(I select corners of a green box, the object turns to dotted, and transcript reports the number of entities selected: "1 found, 1 total")

c [Enter]

(I select corners of a green box again, to select nodes of a different object.  The second object turns to dotted, and the transcript reports "1 found, 2 total")

[Enter]

(I specify a "from point" and "destination", and I expect all selected items to move, but only the nodes selected in the first green box are stretched.)