[libadwaita/wip/exalm/tabs2] tab-box: Fix initial reorder offset

[Alexander Mikhaylenko <alexm src gnome org>]

commit eef4e849321b1a92fe310b54815b95b1b5772972
Author: Alexander Mikhaylenko <alexm gnome org>
Date:   Tue Aug 2 12:35:56 2022 +0400

    tab-box: Fix initial reorder offset
    
    And so we fix the remaining part of the dnd jank.
    
    Fixes https://gitlab.gnome.org/GNOME/libadwaita/-/issues/427

 src/adw-tab-box.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
---
diff --git a/src/adw-tab-box.c b/src/adw-tab-box.c
index 64a9c389..7ff04e59 100644
--- a/src/adw-tab-box.c
+++ b/src/adw-tab-box.c
@@ -1172,6 +1172,7 @@ animate_reorder_offset (AdwTabBox *self,
 {
   gboolean is_rtl = gtk_widget_get_direction (GTK_WIDGET (self)) == GTK_TEXT_DIR_RTL;
   AdwAnimationTarget *target;
+  double start_offset;
 
   offset *= (is_rtl ? -1 : 1);
 
@@ -1179,6 +1180,7 @@ animate_reorder_offset (AdwTabBox *self,
     return;
 
   info->end_reorder_offset = offset;
+  start_offset = info->reorder_offset;
 
   if (info->reorder_animation)
     adw_animation_skip (info->reorder_animation);
@@ -1187,7 +1189,7 @@ animate_reorder_offset (AdwTabBox *self,
                                               reorder_offset_animation_value_cb,
                                               info, NULL);
   info->reorder_animation =
-    adw_timed_animation_new (GTK_WIDGET (self), info->reorder_offset, offset,
+    adw_timed_animation_new (GTK_WIDGET (self), start_offset, offset,
                              REORDER_ANIMATION_DURATION, target);
 
   g_signal_connect_swapped (info->reorder_animation, "done",