Resolved a TODO in stdwndclass_windows.go about deferring WM_NCCREATE to DefWindowProc().
Added a link to the older Layout page on MSDN to prefsize_windows.go.
Removed TODOs about sign extension on Windows; situation resolved.
Resolved TODO about indeterminate ProgressBar repetition by deciding to leave it to the implementation.
Resolved the ACTCTX_FLAG_SET_PROCESS_DEFAULT TODO by deciding to enable this flag for maximum safety. Also added more future plans.
Added the concept of transience to MsgBox() and MsgBoxError(). Individual implementations will come next.
More TODOs.
Implemented the new MsgBox() transience on Windows.
Implemented the new MsgBox() transience behavior on GTK+.
Implemented message box transience on Mac OS X.
More TODOs.