I'm late to the party, and this might not be of any use to the topic, but we have a bunch of blocks here that weren't really created "properly" and they behave this way.
Revision blocks, for example, have many instances of the same attribute tag (ie. Drawn by: XX and Checked by: XX). If the tags are the same, double clicking will not 'go to' the selected attribute... it will bring the first attribute up in the editor. As long as the selected attribute is unique in that block, it will work as expected.
If that helps anyone...