I am also looking for help on this topic, and I've tried many things here but none have worked.
Perhaps it is my setup,
I have an excel table that holds a link, the full link.. http://google.com/blahblahblah .. and I am not sure why it's not working, the links were compiled from copying them from the address bar and putting into excel.
From investigation it looks like there are two broad categories:
1) Controls not inside a Form control using Launch.
2) Controls inside a Form control using Launch.
The most likely cause is the Internet Options > Security Settings/Zones. Please check to see that the site you are running your app in and the site you are trying to launch are not in different/more restricted security zones.
When the Form control is in FormMode = View, it blocks the child control's behavior/actions (OnSelect = Launch in this case). A good workaround is to put the button outside the Form. Another one is to put your Form in Edit mode. We are discussing if we should change that behavior. In parallel we will work on updating documentation so developers are aware of this.