[gimp] app: fix CRITICAL when translating selected content

[Ell <ell src gnome org>]

commit 1e9bf288ba958713ba051886428c77ce8d903357
Author: Ell <ell_se yahoo com>
Date:   Wed Oct 2 18:33:27 2019 +0300

    app: fix CRITICAL when translating selected content
    
    Fix a CRITICAL when creating a floating selection by Alt-dragging a
    selection using one of the selection tools.

 app/tools/gimpeditselectiontool.c | 2 ++
 1 file changed, 2 insertions(+)
---
diff --git a/app/tools/gimpeditselectiontool.c b/app/tools/gimpeditselectiontool.c
index 8f931f6137..f3163770e8 100644
--- a/app/tools/gimpeditselectiontool.c
+++ b/app/tools/gimpeditselectiontool.c
@@ -597,6 +597,8 @@ gimp_edit_selection_tool_update_motion (GimpEditSelectionTool *edit_select,
 
           edit_select->live_items = g_list_prepend (NULL, active_item);
 
+          gimp_viewable_preview_freeze (GIMP_VIEWABLE (active_item));
+
           gimp_item_start_transform (active_item, TRUE);
 
           /*  fallthru  */