Under "Preferences" > "General" I've both "remember-boxes" unchecked (=deselected).
Under "Preferences" > "Video" the only box I've checked/selected is "Borderless Play window"
Under rightclick > Video and its sub-options:
nothing is selected.
My Windows-shortcut works exactly as intended by you (provided BSPlayer is not active when doubleclicking on that shortcut).
(without the "-pan" bit in the commandstring there only remains a narrow band at top and bottom)
What video-rendering do you use (I use Overlay Mode 1). Further what codec/filter does BSPlayer use for playback?
(rightclick > Options > Filters > Advanced)
I'm using DivX and under its "Quality settings" I've selected "Maintain Original" with respect to Aspect Ratio and at the right I've checked all boxes except "Yuv Extended Mode".