android app re-launch issue when app already in background

[BlueIguana]

Hi. I have created a simple android app which launches a training resource webpage using the devices default browser. The webpage to be launched is chosen depending on which course module has been reached – which is stored in a webserver text file. The job of the app is to determine which html file to launch, launch it, and end.
The app works as expected except when a combination occurs: a) the browser page is moved into the background (eg another app is opened) plus b) the user relaunches the app using the icon instead of selecting the instance of the app running in the background. When this combination occurs a grey screen is displayed.
How can I change the app to remove this issue? It seems like the app recognises it is already running but I haven’t found a way to handle this elegantly.
Livecode 7.1.1 Phone android version 5.0.1
SDK:
SDK tools rev 24.4.1
DK platform tools 23.1
Build tools 23.0.2
Android 6 (api 23)
Android 4.1.2 (API 16)
Android 4.0.3 (api 15)
Android 2.3.3 (Api 10)
Android 2.2 (api 8 )

Thanks for any help.
I have attached the stack
Dave