Information:

Hello, first of all, I'd like to let you know that the original author will no longer be updating the original Razor Designer due to the transition to Goo. We've therefore agreed with the original author (xazware) to transfer the development of Razor Designer to me. This means that, from now on, I am the new developer of Razor Designer. Therefore, if you have any questions, suggestions for improvement, or anything else, please direct them to me (you can find me on the official S&box Discord server - sakulmore_official).

Razor Designer

Drag-and-drop UI editor for S&Box

A gorgeous canvas to work on

Every property you'd ever want to change or not change on any UI element you could ever want in one Inspector column

Pseudoclasses - see what happens when you hover or activate a button live on the canvas preview!
Hotkeys - the usual Ctrl+O to open, Ctrl+S to save, you get the idea there are tooltips if you forget them
Pan / Zoom with the mouse wheel . Click it to pan, scroll it to zoom. Easy enough?
Shift dragging - locks to X/Y axis
Alt dragging - resize here and there 
C# variable configuration...yeah i'm excited too it's cool
Play with the arrow keys to nudge stuff around it's awesome.
s&box themed templates ready for you to use! you're lucky i'm so generous...
performance is great (i checked)