[gtk+] xi2: Don't set button mask 4 and 5

[Matthias Clasen <matthiasc src gnome org>]

commit 2feaf8f970d93bf24d0e9036526e451413bc0f2f
Author: Matthias Clasen <mclasen redhat com>
Date:   Sat May 2 11:51:38 2015 -0400

    xi2: Don't set button mask 4 and 5
    
    We interpret buttons 4-7 as old-school scroll events, so it does
    not make sense to add these to the mask. Also fix an off-by-one
    in the loop here, buttons_mask is 1-based.

 gdk/x11/gdkdevice-xi2.c |   12 +++---------
 1 files changed, 3 insertions(+), 9 deletions(-)
---
diff --git a/gdk/x11/gdkdevice-xi2.c b/gdk/x11/gdkdevice-xi2.c
index fad8671..66c3a31 100644
--- a/gdk/x11/gdkdevice-xi2.c
+++ b/gdk/x11/gdkdevice-xi2.c
@@ -762,10 +762,10 @@ _gdk_x11_device_xi2_translate_state (XIModifierState *mods_state,
     {
       gint len, i;
 
-      /* We're only interested in the first 5 buttons */
-      len = MIN (5, buttons_state->mask_len * 8);
+      /* We're only interested in the first 3 buttons */
+      len = MIN (3, buttons_state->mask_len * 8);
 
-      for (i = 0; i < len; i++)
+      for (i = 1; i <= len; i++)
         {
           if (!XIMaskIsSet (buttons_state->mask, i))
             continue;
@@ -781,12 +781,6 @@ _gdk_x11_device_xi2_translate_state (XIModifierState *mods_state,
             case 3:
               state |= GDK_BUTTON3_MASK;
               break;
-            case 4:
-              state |= GDK_BUTTON4_MASK;
-              break;
-            case 5:
-              state |= GDK_BUTTON5_MASK;
-              break;
             default:
               break;
             }