#Create a new file in your home directory called .gtkrc-eclipse

# call eclipse with this command:
# env GTK2_RC_FILES=/usr/share/themes/Clearlooks/gtk-2.0/gtkrc:/home/USER/.gtkrc-eclipse '/path_to_eclipse/eclipse'

# In your Eclipse directory find the file 'plugins/org.eclipse.platform_4.2.*/css/e4_default_gtk.css'
# (there's an * in there, because I guess that the version may change in the future or may be different already).
# In this file there's a CSS class:

#.MPartStack {
#   font-size: 11;
#   swt-simple: false;
#   swt-mru-visible: false;
#}

# And you have two possible solutions:

# 1. Change font-size to something smaller
# 2. Just comment out or remove font-size from this class (works well for me)

# http://stackoverflow.com/questions/11805784/very-large-tabs-in-eclipse-panes-on-ubuntu

# .gtkrc-eclipse

style "gtkcompact" {
  GtkButton::default_border={0,0,0,0}
  GtkButton::default_outside_border={0,0,0,0}
  GtkButtonBox::child_min_width=0
  GtkButtonBox::child_min_heigth=0
  GtkButtonBox::child_internal_pad_x=0
  GtkButtonBox::child_internal_pad_y=0
  GtkMenu::vertical-padding=1
  GtkMenuBar::internal_padding=0
  GtkMenuItem::horizontal_padding=4
  GtkToolbar::internal-padding=0
  GtkToolbar::space-size=0
  GtkOptionMenu::indicator_size=0
  GtkOptionMenu::indicator_spacing=0
  GtkPaned::handle_size=4
  GtkRange::trough_border=0
  GtkRange::stepper_spacing=0
  GtkScale::value_spacing=0
  GtkScrolledWindow::scrollbar_spacing=0
  GtkTreeView::vertical-separator=0
  GtkTreeView::horizontal-separator=0
  GtkTreeView::fixed-height-mode=TRUE
  GtkWidget::focus_padding=0
}
class "GtkWidget" style "gtkcompact"

# Make tabs smaller

style "compact-toolbar" {
  GtkToolbar::internal-padding = 0
  xthickness = 1
  ythickness = 1
}

style "compact-button" {
  xthickness = 0
  ythickness = 0
}

class "GtkToolbar" style "compact-toolbar"
widget_class "*<GtkToolbar>*<GtkButton>" style "compact-button"