When running 2 powerbuilder apps how to you ensure one keeps the focus until closed?

I have a pb app that is a menu, when a option is picked it starts a new pb app by using            run('c:\Program Files\CIS Label Generator\labels.exe' )  that works fine, but sometimes the pc switches back to the menu screen (then it confuses the users) with the label screen is still open.  How to I keep the label screen the screen on the pc until it is closed? then they go back to the menu.