- Windows: cgo, MinGW-w64 (see note below), Windows XP and newer
- **Note**: Notice I specifically said [MinGW-w64](http://mingw-w64.sourceforge.net/) here. This is important: regular MinGW is missing various recent header files which package ui uses, and thus won't build with it. Make sure your MinGW is that version instead. If you're running on Windows and are not sure what to download, get the mingw-builds distribution.
**18 October 2014**<br>The container system was rewritten entirely. You can now set a margin on Windows and Groups and spacing between controls ("padding") on Stacks, Grids, and SimpleGrids. Margins on Tabs will come soon. The work needed to change this will make future additions (like Popover and Spinbox) easier/more sensible. (The Mac OS X code is still glitchy; mind the dust.)
**31 August 2014**<br>Grid is now renamed SimpleGrid in preparation for implementing a more [GtkGrid](https://developer.gnome.org/gtk3/unstable/GtkGrid.html)-like Grid. Mind the change.