I believe it's because gui.drawbox was redefined during an update, and broke some older scripts.
The parameter that currently defines the fill color of the box used to instead define the border color, and the old box drawing had no fill. After the change, any scripts that would use gui.drawbox now defines the fill color and gives the mess you see.
Since it isn't just one script, though, you'll need to look through
x_functions.lua as well, and ctrl+F for any gui.drawbox in both the script you want to use and the one I pointed out. It will use the old way of dealing with boxes, which end up doing fill color.
Old: gui.drawbox(x_topleft, y_topleft, x_bottomright, y_bottomright, bordercolor)
New: gui.drawbox(x_topleft, y_topleft, x_bottomright, y_bottomright, fillcolor, bordercolor)
So the solution would be to insert the string "clear" just before the last parameter, so that we have six parameters instead of five, and have it define the border color like it did long, long ago.
Language: lua
-- Line 31 of SMB-Mouse.lua
gui.drawbox( 6, 28 + i, 250, 92 - i, "#000000");
gui.drawbox( 6, 28 + i, 250, 92 - i, "clear", "#000000");
--Line 40 of SMB-Mouse.lua
gui.drawbox(7, 29, 249, 91, "#ff" .. warningboxcolor .. warningboxcolor);
gui.drawbox(7, 29, 249, 91, "clear", "#ff" .. warningboxcolor .. warningboxcolor);
--Line 59 of x_functions.lua
]] gui.drawbox(x1,y1,x2,y2,color);
]] gui.drawbox(x1,y1,x2,y2,"clear",color);
