Yeah that's the way it works. You might think it should check the condition alongside the mouse trigger at the moment you click; but it just checks for mouse clicks and then goes through each mouse click event one at a time checking the other conditions. So whether a later event runs depends on what happens in a previous event.
What you have there is the equivalent of:
<img src="https://dl.dropbox.com/u/8367729/construct/pics/onclicked1.png" border="0" />
And the solution like superkew says is:
<img src="https://dl.dropbox.com/u/8367729/construct/pics/onclicked2.png" border="0" />