Avernum 3 game, on Win7 Pro 64bit, Greenshot screenshot results in a black pic.
Fix?
From what you write, this might be a general issue Greenshot faces with some games, please see here: https://greenshot.atlassian.net/browse/BUG-2084?focusedCommentId=101901&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-101901