minor change

src/ui/view/GUI.java

@@ -538,7 +538,7 @@ public class GUI<E> implements CategoryListener {
 						controller.paste(null, canvas.getMousePosition());
 				} catch (HeadlessException | JsonParseException | UnsupportedFlavorException | IOException e1) {
 					// TODO Auto-generated catch block
-					JLabel message = new JLabel("The Clipboard information can't be pasted into Application.");
+					JLabel message = new JLabel("The Clipboard information cannot be pasted into Application.");
 					JOptionPane.showMessageDialog(null, message, "", JOptionPane.ERROR_MESSAGE);
 				}
 				canvas.repaint();

src/ui/view/MyCanvas.java

@@ -382,7 +382,7 @@ public class MyCanvas extends JPanel implements MouseListener, MouseMotionListen
 					controller.paste(null, mousePosition);
 				} catch (JsonParseException | UnsupportedFlavorException | IOException e1) {
 					// TODO Auto-generated catch block
-					JLabel message = new JLabel("The Clipboard information can't be pastet into Application.");
+					JLabel message = new JLabel("The Clipboard information cannot be pastet into Application.");
 					JOptionPane.showMessageDialog(null, message, "", JOptionPane.ERROR_MESSAGE);
 				}
 				repaint();

src/ui/view/UpperNodeCanvas.java

@@ -396,7 +396,7 @@ public class UpperNodeCanvas extends JPanel implements MouseListener, MouseMotio
 					controller.paste(upperNode, mousePosition);
 				} catch (JsonParseException | UnsupportedFlavorException | IOException e1) {
 					// TODO Auto-generated catch block
-					JLabel message = new JLabel("The Clipboard information can't be pastet into Application.");
+					JLabel message = new JLabel("The Clipboard information cannot be pastet into Application.");
 					JOptionPane.showMessageDialog(null, message, "", JOptionPane.ERROR_MESSAGE);
 				}
 				repaint();