Unsure if this is just me but this makes using this window nearly impossible. I had to use Ard's client so that I could drag the window upwards and move it off screen just so I could access the "upload" button. And yes, I tested on ender's and vanilla - on all 3 clients it's way too big, just ard's lets me drag it offscreen.
Which begs another question: Why not just let us drag windows from any part of it, instead of only top corners?