app: ensure Window.Invalidate redraws after delivering events

Events such as system.CommandEvent may result in Invalidate being
called. Ensure animation state is properly updated.

Signed-off-by: Elias Naur <mail@eliasnaur.com>

app/window.go

@@ -630,6 +630,7 @@ func (w *Window) waitAck(d driver) {
 		case <-w.immediateRedraws:
 			// Invalidate was called during frame processing.
 			w.setNextFrame(time.Time{})
+			w.updateAnimation(d)
 		}
 	}
 }