When opening new files, they are always added to the newest instance/window, even when drag-dropping files onto older instances/windows. Not sure what the intended behaviour is, but being able to organize pdfs on different instances/windows would be nice.
New Window (secondary instance of main) was a recent addition and has a few oddities since both are in reality one session (not 2 sets of active settings)
Internal File Open or favorites will work independently for each tabbed window, but external send to or drag and drop as you point out goes to the newest, not the currently active.
One way to allow drag and drop or send to multiple sessions is two start two or more sessions as used for dual screen projecting etc. but then the history is not shared.
Yeah that works perfectly. It was really silly of me to not have thought of using the internal File->Open before opening a query. Thanks!