ok, fixed in the next beta release.
Now read this carefully!
GLBasic V11+ defaults to: ALPHATESTING 1; ALPHAMODE -1;
That's faster than cookie cutting on mobile devices. If, however, you do alphamode 0 now, you WILL SEE PINK AREAS! Always do ALPHAMODE -1 - OR - do ALPHATESTING 0.05 to get the old V10 behaviour.
LOCAL id% = GENSPRITE()
// Create virtual screen
CREATESCREEN 1,id%,32,32
USESCREEN 1
DRAWRECT 0,0,31,31,RGB(255,255,255) // white background os the sprite
ALPHATESTING 1 // no cookie cut
ALPHAMODE 0 // no blending
DRAWRECT 4,4,24,24,RGB(255,0,128) // transparent hole in the sprite
USESCREEN -1
DRAWRECT 100,100,70,70,RGB(255,0,0) // draw the red background
ALPHAMODE -1 // blend cookie holes, totally (same but faster than alphatesting .05)
DRAWSPRITE id%,120,120 // draw the sprite
SHOWSCREEN
MOUSEWAIT
END