Merge #12999: qt: Show the Window when double clicking the taskbar icon

67bf2aa qt:Show the entire Window when double clicking on taskbar (Chun Kuan Lee)

Pull request description:

  fix #12838

Tree-SHA512: 4498bc1fe52efeed3768d6bdd7941e4b036d52ae80d9c1b6679c6daa3a62aeda4cff0c91fe1c65afaea6049c59cb0296fdcbff63ecb342d518615a92361fda7f

src/qt/bitcoingui.cpp

@@ -968,6 +968,11 @@ void BitcoinGUI::changeEvent(QEvent *e)
                 QTimer::singleShot(0, this, SLOT(hide()));
                 e->ignore();
             }
+            else if((wsevt->oldState() & Qt::WindowMinimized) && !isMinimized())
+            {
+                QTimer::singleShot(0, this, SLOT(show()));
+                e->ignore();
+            }
         }
     }
 #endif