[balsa/popover] compose window: Pop up the menu at the pointer

[Peter Bloomfield <peterb src gnome org>]

commit ab8b919f86390bf3b84148de84cd3ea858cb6aef
Author: Peter Bloomfield <PeterBloomfield bellsouth net>
Date:   Fri May 8 19:43:34 2020 -0400

    compose window: Pop up the menu at the pointer
    
    Pop up the context menu actually *at* the pointer, not several px
    higher.

 src/sendmsg-window.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)
---
diff --git a/src/sendmsg-window.c b/src/sendmsg-window.c
index dae39c9fd..cfe79e71b 100644
--- a/src/sendmsg-window.c
+++ b/src/sendmsg-window.c
@@ -2433,11 +2433,16 @@ attachment_button_press_cb(GtkWidget * widget, GdkEventButton * event,
            if (attach_info != NULL) {
                if (attach_info->popup_menu != NULL) {
                     GdkRectangle rectangle;
+                    gint x, y;
+
+                    gtk_tree_view_convert_bin_window_to_widget_coords(tree_view,
+                                                                      event->x, event->y,
+                                                                      &x, &y);
 
                     /* Pop up above the pointer */
-                    rectangle.x = event->x;
+                    rectangle.x = x;
                     rectangle.width = 0;
-                    rectangle.y = event->y;
+                    rectangle.y = y;
                     rectangle.height = 0;
                     gtk_popover_set_pointing_to(GTK_POPOVER(attach_info->popup_menu),
                                                 &rectangle);