Right click on your PC Desktop and check your screen resolution. this is the only place I think you have any control over the content appearance of BIAB when the window is resized.

My resolution is 1440 x 900 set to Landscape on a 24 inch widscreen monitor. When BIAB is fully expanded everything looks great, but when downsized it does indeed truncate (with no L/R sliders to adjust). I guess it is the sliders that we need to add to wish list.