BSPlayer should be in full screen mode by default.
(To test if it is, you could e.g. doubletap/click on screen and then tap/click menu (top right), then select "pop up" video. Then double-tap/click on pop-up video window to return to full screen. Anything changed?)
Maybe you intend to use "pan & scan" (in), so that only a "zoomed in" part of the video is shown (which, however, will always result in losing a part of the picture)?
I have an android TV stick too, but I didn't test this only using a mouse sofar. (I don't use the stick with a(n air) mouse as controler, but instead I use a wireless Logitech K400 keyboard, which has a
multitouch touchpad to do the swiping etc.)
I will try to test with a mouse tomorrow.
You probably could try as follows: doubletap/click on screen so that BSPlayer's controls are shown. Then tap/click on the most left button thereof at the bottom (four arrows pointing to the four corners of your screen). By repeatedly tapping/clicking this button you cycle through the available screenmodes. As said earlier you will loose part of the picture but maybe this is what you're looking for?
Please let us know your findings.
