patch 7.4.1402
Problem:    GTK 3 is not supported.
Solution:   Add GTK 3 support. (Kazunobu Kuriyama)
diff --git a/runtime/doc/eval.txt b/runtime/doc/eval.txt
index 022a5da..abc022d 100644
--- a/runtime/doc/eval.txt
+++ b/runtime/doc/eval.txt
@@ -7315,6 +7315,7 @@
 gui_gnome		Compiled with Gnome support (gui_gtk is also defined).
 gui_gtk			Compiled with GTK+ GUI (any version).
 gui_gtk2		Compiled with GTK+ 2 GUI (gui_gtk is also defined).
+gui_gtk3		Compiled with GTK+ 3 GUI (gui_gtk is also defined).
 gui_mac			Compiled with Macintosh GUI.
 gui_motif		Compiled with Motif GUI.
 gui_photon		Compiled with Photon GUI.
diff --git a/runtime/doc/gui.txt b/runtime/doc/gui.txt
index d779763..520eba9 100644
--- a/runtime/doc/gui.txt
+++ b/runtime/doc/gui.txt
@@ -25,7 +25,7 @@
 
 First you must make sure you actually have a version of Vim with the GUI code
 included.  You can check this with the ":version" command, it says "with xxx
-GUI", where "xxx" is X11-Motif, X11-Athena, Photon, GTK, GTK2, etc., or
+GUI", where "xxx" is X11-Motif, X11-Athena, Photon, GTK2, GTK3, etc., or
 "MS-Windows 32 bit GUI version".
 
 How to start the GUI depends on the system used.  Mostly you can run the
@@ -514,11 +514,14 @@
 This does require the |+menu| feature enabled at compile time.
 
 							*tear-off-menus*
-GTK+ and Motif support Tear-off menus.  These are sort of sticky menus or
+GTK+ 2 and Motif support Tear-off menus.  These are sort of sticky menus or
 pop-up menus that are present all the time.  If the resizing does not work
 correctly, this may be caused by using something like "Vim*geometry" in the
 defaults.  Use "Vim.geometry" instead.
 
+As to GTK+ 3, tear-off menus have been deprecated since GTK+ 3.4.
+Accordingly, they are disabled if gvim is linked against GTK+ 3.4 or later.
+
 The Win32 GUI version emulates Motif's tear-off menus.  Actually, a Motif user
 will spot the differences easily, but hopefully they're just as useful.  You
 can also use the |:tearoff| command together with |hidden-menus| to create
@@ -650,8 +653,8 @@
 The priority for the PopUp menu is not used.
 
 The Help menu will be placed on the far right side of the menu bar on systems
-which support this (Motif and GTK+).  For GTK+ 2, this is not done anymore
-because right-aligning the Help menu is now discouraged UI design.
+which support this (Motif and GTK+).  For GTK+ 2 and 3, this is not done
+anymore because right-aligning the Help menu is now discouraged UI design.
 
 You can use a priority higher than 9999, to make it go after the Help menu,
 but that is non-standard and is discouraged.  The highest possible priority is
diff --git a/runtime/doc/gui_x11.txt b/runtime/doc/gui_x11.txt
index f085e2f..605b998 100644
--- a/runtime/doc/gui_x11.txt
+++ b/runtime/doc/gui_x11.txt
@@ -369,6 +369,16 @@
 you might have to use the file ~/.gtkrc-2.0 instead, depending on your
 distribution.
 
+For GTK+ 3, an effect similar to the above can be obtained by adding the
+following snippet of CSS code to $XDG_HOME_DIR/gtk-3.0/gtk.css (usually,
+$HOME/.config/gtk-3.0/gtk.css):
+ >
+	.tooltip {
+		background-color: #ffffcc;
+		color: #000000;
+	}
+<
+
 Using Vim as a GTK+ plugin				*gui-gtk-socketid*
 
 When the GTK+ version of Vim starts up normally, it creates its own top level