Layout editor

NOTE: MyGUI does not support plugins for Mac OSX yet (https://github.com/MyGUI/mygui/issues/42), so editing OpenMW layouts is currently not possible on that platform.

• Install MyGUI version 3.2.2 from https://github.com/MyGUI/mygui.
• Rebuild OpenMW against the new MyGUI version you just installed. An OpenMW version from git master (39b6659045ae07c7c4539efbb46241dd288fc59e or later) is currently required, which includes a MyGUI Plugin library called Plugin_MyGUI_OpenMW_Resources.
• Copy the Plugin_MyGUI_OpenMW_Resources library file from the OpenMW build folder to the directory you will be running the MyGUI Layout Editor from (most likely the "bin" subdirectory in MyGUI's build directory).
• Start the MyGUI LayoutEditor.
• Go to File -> Settings -> Folders, press Add and select the folder in your OpenMW repository containing the MyGUI layouts (files/mygui)
• Go to File -> Settings -> Resources, press Add, type core_layouteditor.xml, then press Enter.
• Restart the LayoutEditor and try to load a .layout file from OpenMW. It should be working now!
• Note that when you save a layout, you need to run OpenMW's cmake script in order to copy it to OpenMW's build folder, so that the new layout is used when you start OpenMW.