GtkExtra is a useful set of widgets for creating GUI's for the Xwindows system
using GTK+.  You can use it complementary to GTK+ and it is written in C.  It
is also Free Software and released under the LGPL license.

  The library includes the following widgets:

  * GtkSheet, a matrix widget
  * GtkPlot, a widget for drawing high quality scientific plots in
    two dimensions
  * GtkIconList, a GtkFixed subclass that allows you to display a
    table of xpm icons with editable labels
  * GtkDirTree, a GtkCTree subclass for navigating the file-system
  * GtkFileList, a GtkIconList subclass that displays the contents
    of a given directory using fancy icons for different types of files
  * GtkIconFileSelection, a nice looking file selection dialog
  * GtkItemEntryGtkItemEntry, a GtkEntry subclass
  * GtkFontCombo, a GtkToolBar subclass for selecting fonts
  * GtkComboBox, a composite widget with two buttons
  * GtkColorCombo, a GtkComboBox subclass for selecting colours
  * GtkBorderCombo, a GtkComboBox subclass for selecting border styles
  * GtkCheckItem, a check button with the look and feel of Redmond95

Homepage:
https://gtkextra.sourceforge.net/
