Layout has several study Bibles in a floating window. Selected text in the Jewish Study Bible and clicked the add drop down in the Bibliography tool. Clicked the Selected Text option. Logos added the Lexham Hebrew Bible to the bibliography (this was the last pane selected in the main window). Tried this with the floating window on both displays, and the resulting bibliographic entry would alway be the last selected pane in the main window.
However, if memory serves, the initial entry into this bibliography did come from an entire article selected from JBL which was in a floating window on the secondary display at the time.
Add All Open Resources does correctly include resources in floating windows.