Fixes #674 Mouse Double Click propagation.

Terminal.Gui/ConsoleDrivers/WindowsDriver.cs

@@ -759,7 +759,7 @@ namespace Terminal.Gui {
 				IsButtonReleased = false;
 			}
 
-			if ((mouseEvent.EventFlags == 0 && LastMouseButtonPressed == null && !IsButtonDoubleClicked) ||
+			if ((mouseEvent.ButtonState != 0 && mouseEvent.EventFlags == 0 && LastMouseButtonPressed == null && !IsButtonDoubleClicked) ||
 				(mouseEvent.EventFlags == WindowsConsole.EventFlags.MouseMoved &&
 				mouseEvent.ButtonState != 0 && !IsButtonReleased && !IsButtonDoubleClicked)) {
 				switch (mouseEvent.ButtonState) {