[gegl] bin: allow editing commandline while scrollback is visible

[Øyvind "pippin" Kolås <ok src gnome org>]

commit a50d771c8739295b9873f30b634443c62c25a162
Author: Øyvind Kolås <pippin gimp org>
Date:   Tue Apr 23 00:53:16 2019 +0200

    bin: allow editing commandline while scrollback is visible

 bin/ui-core.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)
---
diff --git a/bin/ui-core.c b/bin/ui-core.c
index 7e722ebaf..b11bbf973 100644
--- a/bin/ui-core.c
+++ b/bin/ui-core.c
@@ -4654,10 +4654,17 @@ static void ui_commandline (Mrg *mrg, void *data)
   }
  else
   {
-    mrg_set_xy (mrg, 0,h*2);
-    mrg_edit_start (mrg, update_commandline, o);
-    mrg_printf (mrg, "%s", o->commandline);
-    mrg_edit_end (mrg);
+    if (o->commandline[0])
+    {
+      mrg_set_xy (mrg, 0,h*2);
+      mrg_edit_start (mrg, update_commandline, o);
+      mrg_printf (mrg, "%s", o->commandline);
+      mrg_edit_end (mrg);
+    }
+    else
+    {
+      mrg_add_binding (mrg, "unhandled", NULL, "start entering commandline", cmd_unhandled, NULL);
+    }
   }
 
 jump:
@@ -7996,6 +8003,7 @@ meta_swap_children (GeState *state,const char *path,
   fprintf (stderr, "%s NYI\n", __FUNCTION__);
 }
 
+
 void
 meta_set_attribute (GeState    *state,
                     const char *path,