The GUI is one of the trickier things, and there just isn't room on the left while still having the tooltips over there and also having room for the wave warnings, etc. I wish this was easier, but because people can play in any aspect ratio and resolution, the math actually gets pretty hard to do efficiently while still keeping the parts of the GUI at a same-relative-size view for you and not having a cascade of resizes of every element in them. We've done our best, but I'm still not super happy with the level of flexibility we have there.
Please don't mistake -- GUI requests are absolutely welcome, and we can make various things an option, or make changes of course. But this is one where there are elements above and below and over top of where the build menu would go, and I just can't fit that there. I'm sorry!