Backport of PR #157 -- Fixing textbox issue with polish letter ą

Greenshot/Drawing/TextContainer.cs

@@ -1,20 +1,20 @@
 /*
  * Greenshot - a free and open source screenshot tool
  * Copyright (C) 2007-2020 Thomas Braun, Jens Klingen, Robin Krom
- * 
+ *
  * For more information see: http://getgreenshot.org/
  * The Greenshot project is hosted on GitHub https://github.com/greenshot/greenshot
- * 
+ *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation, either version 1 of the License, or
  * (at your option) any later version.
- * 
+ *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
- * 
+ *
  * You should have received a copy of the GNU General Public License
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
@@ -492,7 +492,7 @@ namespace Greenshot.Drawing
                 e.SuppressKeyPress = true;
             }
 
-            if (e.Control && e.KeyCode == Keys.A)
+            if (e.Control && !e.Alt && e.KeyCode == Keys.A)
             {
                 _textBox.SelectAll();
             }