How to play just one animation at a time in NGUI's UIPlayAnimation?

I’m currently making an android game and I’m using NGUI for the UI part. I have attached PlayAnimation component to the buttons and use it to animate the menu transitions. The problem is if I touch one button, the menu transition’s properly. But if i touch a button and then touch another button before the transition animation is complete, I get two menus overlapping each other.
For instance if i press Settings button and store button together, I get both store menu and settings menu on the screen overlapping each other.
I need to animate the transition only when another animation is ended. Please help!!
And thanks in advance…

I am not using playAnimation component for ngui animation.But may be your problem is solved through depth of button.You can change depth on run time by code easily.