Return to Previous App not working

[apwood]

I was hoping to use commandr to control brightness and volume when I'm running my SatNav app (Route 66 Navigate), and also hopefully to phone contacts. When I use OK Google, for example to phone a contact, it opens a page that doesn't disappear when it's finished, thereby covering up my navigation app; so I can only then get back to the app by touching the phone - I'm trying to go handsfree here! So I hoped that commandr, especially with its "return to previous app" setting would fix this.

It doesn't, in fact it makes things worse. If I only have my navigation app running and say "ok Google: volume 60" - it does change the volume BUT it then opens all the following screens, the first of which is in front of my navigation app:

A web page with search results for volume 60
A google app pages that says "Get Now cards"

The same happens with the command Screen Brightness x

I haven't enabled any Google Now cards, but can't find any way to completely disable Google Now - the only settings are via the google app or the google settings app. I haven't installed Google Now Launcher, just using the stock launcher that comes with my Samsung Galaxy S4 (with latest Lollipop OTA upgrade).