Hi Severin,
I was able to replicate your issue in Design Studio 1.5. This seems to be an unusual timing issue. I was able to workaround it with the following approach:
1. Install the Timer component from the Real Time Package (This component is now standard in Design Studio 1.6) and place the component anywhere on your canvas;
2. Implement the following code in your button's "On Click" event script:
APPLICATION.openNewWindow("... Query1 ...");
TIMER_1.start();
3. Implement the following code in the "On Timer" event script of the Timer component:
me.stop();
APPLICATION.openNewWindow("... Query2 ...");
Let me know if that works for you,
Mustafa.








