[gnome-subtitles] Fixed copy/cut buttons' sensitivity

[Pedro Castro <pcastro src gnome org>]

commit 6780d9a3eb248a3ae0591b484d0ae564e63b9d4a
Author: Pedro Castro <pedro gnomesubtitles org>
Date:   Sun Jul 8 21:51:14 2018 +0100

    Fixed copy/cut buttons' sensitivity

 src/GnomeSubtitles/Core/Clipboards.cs | 47 +++++++++++++++++++++--------------
 1 file changed, 28 insertions(+), 19 deletions(-)
---
diff --git a/src/GnomeSubtitles/Core/Clipboards.cs b/src/GnomeSubtitles/Core/Clipboards.cs
index ce3ebff..bf2b243 100644
--- a/src/GnomeSubtitles/Core/Clipboards.cs
+++ b/src/GnomeSubtitles/Core/Clipboards.cs
@@ -1,6 +1,6 @@
 /*
  * This file is part of Gnome Subtitles.
- * Copyright (C) 2006-2008 Pedro Castro
+ * Copyright (C) 2006-2018 Pedro Castro
  *
  * Gnome Subtitles is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -19,7 +19,6 @@
 
 using Gtk;
 using System;
-using SubLib;
 
 namespace GnomeSubtitles.Core {
 
@@ -48,23 +47,6 @@ public class Clipboards {
                }
        }
 
-       public void OnOwnerChange (object o, OwnerChangeArgs args) {
-       Window window = Base.Ui.Window;
-
-       if ((!window.IsActive) || (args.Event.Owner == 0) || (!ValidWidgetHasFocus()))
-               Base.Ui.Menus.SetCutCopySensitivity(false);
-       else {
-               Base.Ui.Menus.SetCutCopySensitivity(true);
-       }
-    }
-
-    public bool ValidWidgetHasFocus () {
-       SpinButton start, end, duration;
-       TextView textEdit, translationEdit;
-       Base.Ui.Edit.GetEditableWidgets (out start, out end, out duration, out textEdit, out translationEdit);
-       return start.HasFocus || end.HasFocus || duration.HasFocus || textEdit.HasFocus || 
translationEdit.HasFocus;
-    }
-
     public void Copy () {
        Widget widget = Base.Ui.Window.Focus;
        if (widget is SpinButton)
@@ -88,6 +70,33 @@ public class Clipboards {
        else if (widget is TextView)
                (widget as TextView).Buffer.PasteClipboard(clipboard);
     }
+    
+    private bool ValidWidgetHasFocus () {
+       SpinButton start, end, duration;
+       TextView textEdit, translationEdit;
+       Base.Ui.Edit.GetEditableWidgets (out start, out end, out duration, out textEdit, out translationEdit);
+       return start.HasFocus || end.HasFocus || duration.HasFocus || textEdit.HasFocus || 
translationEdit.HasFocus;
+    }
+    
+    private bool IsCutCopyAvailable (Clipboard clipboard) {
+       if (!Base.Ui.Window.IsActive) {
+               return false;
+               }
+               
+               string text = clipboard.WaitForText();
+               if (String.IsNullOrEmpty(text)) {
+                       return false;
+               }
+               
+               return ValidWidgetHasFocus();
+    }
+    
+    
+    /* Event members */
+    
+    private void OnOwnerChange (object o, OwnerChangeArgs args) {
+               Base.Ui.Menus.SetCutCopySensitivity(IsCutCopyAvailable(o as Clipboard));
+    }
 
 }