[Gtk] Alt-Tab hi-res icons work only for .desktop files?

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http://ubuntuforums.org – Hi, In the Alt+Tab list of currently running app icons a hi-res version of an app icon is only displayed if the app has an associated .desktop file (which specifies the icon, say, "icon-name"). The older/general way of setting the icon: PHP Code: myWindow->set_icon(Gtk::IconTheme::get_default()->load_icon("icon-name",        128, Gtk::ICON_LOOKUP_USE_BUILTIN));  displays a lower-res (blurred) icon in the Alt-Tab menu regardless of the resolution of the loaded icon (in this case a 128x12 (Hardware)