Hi,
Some more informatin on $subject and related topics.
--
At the time when gtk_widget_get_window(main_widgets.window) is invoked, there is indeed no main window (GetActionWindow() returns NULL).
Since this is about reopening files on startup, their shortcuts, if any, were already resolved when the files were open in the first place. The right thing to do is probably instruct document_open_file_full() not resolve them again.
--
There are lots of warnings about implicit declaration of function 'win32_...', probably a result of "include what you use" (and not specific to gtk+3).
--
With gtk+3, pressing "down" to scroll in a source file gives CPU usage of 50% (that is, 100% on a single cores), and the scrolling is a bit jumpy. For reference, gtk+2 uses 22% CPU, and SciTE for Win32 only 9% (due to the fact is uses Win32 API directly).
--
With gtk+3, when I have a selected tree view row in an unfocused tree view, it's displayed in gray as usual (with the default theme), but positioning the mouse over it alters the display, showing any check boxes (GtkCellRendererToggle) as unchecked. gtk+2 is OK.
--
The plugins do not build with the latest Geany, due to a bug in Geany wscript: 'localedir': '${datarootdir/locale' is missing "}".
--
I wrote simple gtk+3 support for geany plugins wscript, but have only tested it under windows so far, not linux.
--
Scope does not currently build with gtk+3; I wrote a fix and will send it when I can [1]. GtkTextView works without problems, so the blocking of Geany About Dialog is not because of GtkTextView per se.
--
[1] Last, there was a large storm at my town (g:varna flood), and the internet is unstable, so I'll probably use mail only for a few days, not svn or git.