[gimp/gimp-2-10] app: increase GimpSelectionTools idle priority to avoid flickering

[Ell <ell src gnome org>]

commit 30788227cc451190327560a2ae46f2222c92953c
Author: Ell <ell_se yahoo com>
Date:   Thu Apr 25 09:51:38 2019 -0400

    app: increase GimpSelectionTools idle priority to avoid flickering
    
    In gimp_selection_tool_start_change(), increase the priority of the
    idle source used for hiding the selection so that it's run before
    the canvas is redrawn, to avoid flickering the previous selection.
    
    (cherry picked from commit 3369958525bd301cd3887dd55c354593d07fba54)

 app/tools/gimpselectiontool.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)
---
diff --git a/app/tools/gimpselectiontool.c b/app/tools/gimpselectiontool.c
index 018534261c..45192e0799 100644
--- a/app/tools/gimpselectiontool.c
+++ b/app/tools/gimpselectiontool.c
@@ -708,9 +708,10 @@ gimp_selection_tool_start_change (GimpSelectionTool *sel_tool,
            * restarting the selection if we don't visit the main loop between
            * the start_change() and end_change() calls.
            */
-          sel_tool->idle_id = g_idle_add (
+          sel_tool->idle_id = g_idle_add_full (
+            G_PRIORITY_HIGH_IDLE,
             (GSourceFunc) gimp_selection_tool_idle,
-            sel_tool);
+            sel_tool, NULL);
         }
     }