Rereading your post I had a few more thoughts:
As I understand your program...
1) You hover over the button. A text box "username and password" appears.
2) You click the button. An animation plays and the text box is replaced by another reading "authentication"
3) After the animation has played the next button appears.
If at this point you reclick the first button the animation plays but the text boxes are not reset.
At present the only way to reset the text boxes is by moving the cursor off and back onto the first button.
Am I following so far?...
With only the exe file and no publication it's hard to know what triggers you've used and troubleshoot, but the only thing that springs to mind as a possible worksaround is using a variable to record whether the button has already been clicked once.
If is
hasn't then you only play the animation bits (from step 2) (because the intial text has already been displayed by the mouse over in step 1)
If if
has been clicked once, and you're just reclicking it then you repeat the whole sequence of actions starting with hiding and reshowing the text boxes from step 1.
Now I'm not sure if I'm making sense...
Good luck.