That's what I figured. Here's what Steven said about dragging from Windows Explorer.
tracks are drag/dropped in the order they have been selected. In the main panel, if you do the initial selection in one go (eg. clicking on an album picture or using the shift key) then that will be the order the files are displayed. If you do the initial selection from Windows Explorer, then windows has a (what i think) wacky scheme where (if i recall correctly) the ordering starts from the file you are pointing to when you start the drag and wraps the ordering around to the first file.
Then I'd consider your problem's now resolved.
Wow, that's actually it! I wasn't aware of such behaviour, but that is actually very useful to know!
I have tested several times right now - and that makes perfect sense now... I just tested with a few album, and drag&dropped with the mouse over the first tune in an album, and that makes them add correctly to Now Playing.
I feel a bit dumbfounded, but thank you so much for clearing this up!
I have marked the topic as [solved] - now my next step is to donate to help keep this wonderful player alive. <3 MB