In fact there were two issues:
1. GtkFlowBoxChild with "can-focus"==FALSE should pass the focus
to its child immediately.
2. GtkFlowBox with "can-focus"==FALSE should cease its custom keynav
implementation and fall back to the default GtkContainer behavior
which is more natural.
Thanks to these changes the flow box can act as a better replacement
for GtkGrid and similar containers.
https://bugzilla.gnome.org/show_bug.cgi?id=753371
GtkFlowBox is a container that its children in a reflowing
grid, which can be oriented horizontally or vertically.
It is similar to GtkListBox in that the children can
be sorted and filtered, and by requiring a dedicated child
widget type, GtkFlowBoxChild. It is similar to GtkTreeView
in that is supports a full set of selection modes, including
rubberband selection.
This is the culmination of work that has happened in the
egg-list-box module, and earlier in libegg. The origins of
this code are the EggSpreadTable in libegg, which was written
by Tristan van Berkom. It was moved to egg-list-box and
renamed EggFlowBox by Jon McCann, and I gave it some finishing
touched in the flowbox-improvements branch of that module.
