Open https://en.wikipedia.org/wiki/User:Neil_P._Quinn-WMF/T106905?veaction=edit, which contains the wikitext:

[[File:Green_Square.svg|right|thumb|An example image.]]
 A preformatted block.

Try to select both the image and the preformatted block, either by clicking and dragging or by using shift and the up arrow key. You can't.